doc: use sentence-case for headings in docs

PR-URL: nodejs#33889
Refs: https://developers.google.com/style/capitalization#capitalization-in-titles-and-headings
Refs: https://docs.microsoft.com/en-us/style-guide/capitalization
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: Trott

doc/api/addons.md

@@ -1,4 +1,4 @@
-# C++ Addons
+# C++ addons
 
 <!--introduced_in=v0.10.0-->
 <!-- type=misc -->
@@ -395,7 +395,7 @@ only the symbols exported by Node.js will be available.
 source image. Using this option, the Addon will have access to the full set of
 dependencies.
 
-### Loading Addons using `require()`
+### Loading addons using `require()`
 
 The filename extension of the compiled Addon binary is `.node` (as opposed
 to `.dll` or `.so`). The [`require()`][require] function is written to look for
@@ -410,7 +410,7 @@ there is a file `addon.js` in the same directory as the binary `addon.node`,
 then [`require('addon')`][require] will give precedence to the `addon.js` file
 and load it instead.
 
-## Native Abstractions for Node.js
+## Native abstractions for Node.js
 
 Each of the examples illustrated in this document make direct use of the
 Node.js and V8 APIs for implementing Addons. The V8 API can, and has, changed

doc/api/async_hooks.md

@@ -1,4 +1,4 @@
-# Async Hooks
+# Async hooks
 
 <!--introduced_in=v8.1.0-->
 
@@ -127,7 +127,7 @@ class MyAddedCallbacks extends MyAsyncCallbacks {
 const asyncHook = async_hooks.createHook(new MyAddedCallbacks());
 ```
 
-##### Error Handling
+##### Error handling
 
 If any `AsyncHook` callbacks throw, the application will print the stack trace
 and exit. The exit path does follow that of an uncaught exception, but
@@ -201,7 +201,7 @@ be called again until enabled.
 
 For API consistency `disable()` also returns the `AsyncHook` instance.
 
-#### Hook Callbacks
+#### Hook callbacks
 
 Key events in the lifetime of asynchronous events have been categorized into
 four areas: instantiation, before/after the callback is called, and when the
@@ -628,7 +628,7 @@ only on chained promises. That means promises not created by `then()`/`catch()`
 will not have the `before` and `after` callbacks fired on them. For more details
 see the details of the V8 [PromiseHooks][] API.
 
-## JavaScript Embedder API
+## JavaScript embedder API
 
 Library developers that handle their own asynchronous resources performing tasks
 like I/O, connection pooling, or managing callback queues may use the

doc/api/buffer.md

@@ -53,7 +53,7 @@ const buf6 = Buffer.from('tést');
 const buf7 = Buffer.from('tést', 'latin1');
 ```
 
-## Buffers and Character Encodings
+## Buffers and character encodings
 <!-- YAML
 changes:
   - version: v6.4.0
@@ -2640,7 +2640,7 @@ deprecated: v6.0.0
 
 See [`Buffer.allocUnsafeSlow()`][].
 
-## Buffer Constants
+## Buffer constants
 <!-- YAML
 added: v8.2.0
 -->

doc/api/child_process.md

@@ -1,4 +1,4 @@
-# Child Process
+# Child process
 
 <!--introduced_in=v0.10.0-->
 
@@ -70,7 +70,7 @@ For certain use cases, such as automating shell scripts, the
 the synchronous methods can have significant impact on performance due to
 stalling the event loop while spawned processes complete.
 
-## Asynchronous Process Creation
+## Asynchronous process creation
 
 The [`child_process.spawn()`][], [`child_process.fork()`][], [`child_process.exec()`][],
 and [`child_process.execFile()`][] methods all follow the idiomatic asynchronous
@@ -153,7 +153,7 @@ changes:
   * `env` {Object} Environment key-value pairs. **Default:** `process.env`.
   * `encoding` {string} **Default:** `'utf8'`
   * `shell` {string} Shell to execute the command with. See
-    [Shell Requirements][] and [Default Windows Shell][]. **Default:**
+    [Shell requirements][] and [Default Windows shell][]. **Default:**
     `'/bin/sh'` on Unix, `process.env.ComSpec` on Windows.
   * `timeout` {number} **Default:** `0`
   * `maxBuffer` {number} Largest amount of data in bytes allowed on stdout or
@@ -270,8 +270,8 @@ changes:
     done on Windows. Ignored on Unix. **Default:** `false`.
   * `shell` {boolean|string} If `true`, runs `command` inside of a shell. Uses
     `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
-    shell can be specified as a string. See [Shell Requirements][] and
-    [Default Windows Shell][]. **Default:** `false` (no shell).
+    shell can be specified as a string. See [Shell requirements][] and
+    [Default Windows shell][]. **Default:** `false` (no shell).
 * `callback` {Function} Called with the output when process terminates.
   * `error` {Error}
   * `stdout` {string|Buffer}
@@ -355,7 +355,7 @@ changes:
     **Default:** `process.execArgv`.
   * `serialization` {string} Specify the kind of serialization used for sending
     messages between processes. Possible values are `'json'` and `'advanced'`.
-    See [Advanced Serialization][] for more details. **Default:** `'json'`.
+    See [Advanced serialization][] for more details. **Default:** `'json'`.
   * `silent` {boolean} If `true`, stdin, stdout, and stderr of the child will be
     piped to the parent, otherwise they will be inherited from the parent, see
     the `'pipe'` and `'inherit'` options for [`child_process.spawn()`][]'s
@@ -434,11 +434,11 @@ changes:
   * `gid` {number} Sets the group identity of the process (see setgid(2)).
   * `serialization` {string} Specify the kind of serialization used for sending
     messages between processes. Possible values are `'json'` and `'advanced'`.
-    See [Advanced Serialization][] for more details. **Default:** `'json'`.
+    See [Advanced serialization][] for more details. **Default:** `'json'`.
   * `shell` {boolean|string} If `true`, runs `command` inside of a shell. Uses
     `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
-    shell can be specified as a string. See [Shell Requirements][] and
-    [Default Windows Shell][]. **Default:** `false` (no shell).
+    shell can be specified as a string. See [Shell requirements][] and
+    [Default Windows shell][]. **Default:** `false` (no shell).
   * `windowsVerbatimArguments` {boolean} No quoting or escaping of arguments is
     done on Windows. Ignored on Unix. This is set to `true` automatically
     when `shell` is specified and is CMD. **Default:** `false`.
@@ -699,7 +699,7 @@ see [V8 issue 7381](https://bugs.chromium.org/p/v8/issues/detail?id=7381).
 
 See also: [`child_process.exec()`][] and [`child_process.fork()`][].
 
-## Synchronous Process Creation
+## Synchronous process creation
 
 The [`child_process.spawnSync()`][], [`child_process.execSync()`][], and
 [`child_process.execFileSync()`][] methods are synchronous and will block the
@@ -755,8 +755,8 @@ changes:
     normally be created on Windows systems. **Default:** `false`.
   * `shell` {boolean|string} If `true`, runs `command` inside of a shell. Uses
     `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
-    shell can be specified as a string. See [Shell Requirements][] and
-    [Default Windows Shell][]. **Default:** `false` (no shell).
+    shell can be specified as a string. See [Shell requirements][] and
+    [Default Windows shell][]. **Default:** `false` (no shell).
 * Returns: {Buffer|string} The stdout from the command.
 
 The `child_process.execFileSync()` method is generally identical to
@@ -804,7 +804,7 @@ changes:
     **Default:** `'pipe'`.
   * `env` {Object} Environment key-value pairs. **Default:** `process.env`.
   * `shell` {string} Shell to execute the command with. See
-    [Shell Requirements][] and [Default Windows Shell][]. **Default:**
+    [Shell requirements][] and [Default Windows shell][]. **Default:**
     `'/bin/sh'` on Unix, `process.env.ComSpec` on Windows.
   * `uid` {number} Sets the user identity of the process. (See setuid(2)).
   * `gid` {number} Sets the group identity of the process. (See setgid(2)).
@@ -884,8 +884,8 @@ changes:
     **Default:** `'buffer'`.
   * `shell` {boolean|string} If `true`, runs `command` inside of a shell. Uses
     `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
-    shell can be specified as a string. See [Shell Requirements][] and
-    [Default Windows Shell][]. **Default:** `false` (no shell).
+    shell can be specified as a string. See [Shell requirements][] and
+    [Default Windows shell][]. **Default:** `false` (no shell).
   * `windowsVerbatimArguments` {boolean} No quoting or escaping of arguments is
     done on Windows. Ignored on Unix. This is set to `true` automatically
     when `shell` is specified and is CMD. **Default:** `false`.
@@ -1025,7 +1025,7 @@ message might not be the same as what is originally sent.
 If the `serialization` option was set to `'advanced'` used when spawning the
 child process, the `message` argument can contain data that JSON is not able
 to represent.
-See [Advanced Serialization][] for more details.
+See [Advanced serialization][] for more details.
 
 ### `subprocess.channel`
 <!-- YAML
@@ -1543,21 +1543,21 @@ This impacts output that includes multibyte character encodings such as UTF-8 or
 UTF-16. For instance, `console.log('中文测试')` will send 13 UTF-8 encoded bytes
 to `stdout` although there are only 4 characters.
 
-## Shell Requirements
+## Shell requirements
 
 The shell should understand the `-c` switch. If the shell is `'cmd.exe'`, it
 should understand the `/d /s /c` switches and command line parsing should be
 compatible.
 
-## Default Windows Shell
+## Default Windows shell
 
 Although Microsoft specifies `%COMSPEC%` must contain the path to
 `'cmd.exe'` in the root environment, child processes are not always subject to
 the same requirement. Thus, in `child_process` functions where a shell can be
 spawned, `'cmd.exe'` is used as a fallback if `process.env.ComSpec` is
 unavailable.
 
-## Advanced Serialization
+## Advanced serialization
 <!-- YAML
 added:
  - v13.2.0
@@ -1578,7 +1578,7 @@ Therefore, this feature requires opting in by setting the
 `serialization` option to `'advanced'` when calling [`child_process.spawn()`][]
 or [`child_process.fork()`][].
 
-[Advanced Serialization]: #child_process_advanced_serialization
+[Advanced serialization]: #child_process_advanced_serialization
 [`'disconnect'`]: process.html#process_event_disconnect
 [`'error'`]: #child_process_event_error
 [`'exit'`]: #child_process_event_exit
@@ -1611,8 +1611,8 @@ or [`child_process.fork()`][].
 [`subprocess.stdio`]: #child_process_subprocess_stdio
 [`subprocess.stdout`]: #child_process_subprocess_stdout
 [`util.promisify()`]: util.html#util_util_promisify_original
-[Default Windows Shell]: #child_process_default_windows_shell
+[Default Windows shell]: #child_process_default_windows_shell
 [HTML structured clone algorithm]: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm
-[Shell Requirements]: #child_process_shell_requirements
+[Shell requirements]: #child_process_shell_requirements
 [synchronous counterparts]: #child_process_synchronous_process_creation
 [v8.serdes]: v8.html#v8_serialization_api

doc/api/cli.md

@@ -1,4 +1,4 @@
-# Command Line Options
+# Command line options
 
 <!--introduced_in=v5.9.1-->
 <!--type=misc-->
@@ -162,7 +162,7 @@ added: v12.12.0
 
 > Stability: 1 - Experimental
 
-Enable experimental Source Map V3 support for stack traces.
+Enable experimental Source Map v3 support for stack traces.
 
 Currently, overriding `Error.prepareStackTrace` is ignored when the
 `--enable-source-maps` flag is set.
@@ -1132,7 +1132,7 @@ added: v0.1.3
 
 Print node's version.
 
-## Environment Variables
+## Environment variables
 
 ### `NODE_DEBUG=module[,…]`
 <!-- YAML
@@ -1409,7 +1409,7 @@ easier to instrument applications that call the `child_process.spawn()` family
 of functions. `NODE_V8_COVERAGE` can be set to an empty string, to prevent
 propagation.
 
-#### Coverage Output
+#### Coverage output
 
 Coverage is output as an array of [ScriptCoverage][] objects on the top-level
 key `result`:
@@ -1426,16 +1426,16 @@ key `result`:
 }
 ```
 
-#### Source Map Cache
+#### Source map cache
 
 > Stability: 1 - Experimental
 
-If found, Source Map data is appended to the top-level key `source-map-cache`
+If found, source map data is appended to the top-level key `source-map-cache`
 on the JSON coverage object.
 
 `source-map-cache` is an object with keys representing the files source maps
 were extracted from, and values which include the raw source-map URL
-(in the key `url`), the parsed Source Map V3 information (in the key `data`),
+(in the key `url`), the parsed Source Map v3 information (in the key `data`),
 and the line lengths of the source file (in the key `lineLengths`).
 
 ```json
@@ -1544,7 +1544,7 @@ options are of interest only to V8 developers. Despite this, there is a small
 set of V8 options that are widely applicable to Node.js, and they are
 documented here:
 
-### `--max-old-space-size=SIZE` (in Mbytes)
+### `--max-old-space-size=SIZE` (in megabytes)
 
 Sets the max memory size of V8's old memory section. As memory
 consumption approaches the limit, V8 will spend more time on

doc/api/cluster.md

@@ -52,7 +52,7 @@ Worker 5644 started
 
 On Windows, it is not yet possible to set up a named pipe server in a worker.
 
-## How It Works
+## How it works
 
 <!--type=misc-->
 
@@ -753,7 +753,7 @@ changes:
     `undefined` (inherits from parent process).
   * `serialization` {string} Specify the kind of serialization used for sending
     messages between processes. Possible values are `'json'` and `'advanced'`.
-    See [Advanced Serialization for `child_process`][] for more details.
+    See [Advanced serialization for `child_process`][] for more details.
     **Default:** `false`.
   * `silent` {boolean} Whether or not to send output to parent's stdio.
     **Default:** `false`.
@@ -883,5 +883,5 @@ socket.on('data', (id) => {
 [`process` event: `'message'`]: process.html#process_event_message
 [`server.close()`]: net.html#net_event_close
 [`worker.exitedAfterDisconnect`]: #cluster_worker_exitedafterdisconnect
-[Advanced Serialization for `child_process`]: child_process.html#child_process_advanced_serialization
+[Advanced serialization for `child_process`]: child_process.html#child_process_advanced_serialization
 [Child Process module]: child_process.html#child_process_child_process_fork_modulepath_args_options

doc/api/crypto.md

@@ -1579,7 +1579,7 @@ added: v6.3.0
 
 * Returns: {Object} An object containing commonly used constants for crypto and
   security related operations. The specific constants currently defined are
-  described in [Crypto Constants][].
+  described in [Crypto constants][].
 
 ### `crypto.DEFAULT_ENCODING`
 <!-- YAML
@@ -3045,7 +3045,7 @@ key may be passed for `key`.
 
 ## Notes
 
-### Legacy Streams API (prior to Node.js 0.10)
+### Legacy streams API (prior to Node.js 0.10)
 
 The Crypto module was added to Node.js before there was the concept of a
 unified Stream API, and before there were [`Buffer`][] objects for handling
@@ -3056,7 +3056,7 @@ and returned `'latin1'` encoded strings by default rather than `Buffer`s. This
 default was changed after Node.js v0.8 to use [`Buffer`][] objects by default
 instead.
 
-### Recent ECDH Changes
+### Recent ECDH changes
 
 Usage of `ECDH` with non-dynamically generated key pairs has been simplified.
 Now, [`ecdh.setPrivateKey()`][] can be called with a preselected private key
@@ -3164,12 +3164,12 @@ try {
 console.log(receivedPlaintext);
 ```
 
-## Crypto Constants
+## Crypto constants
 
 The following constants exported by `crypto.constants` apply to various uses of
 the `crypto`, `tls`, and `https` modules and are generally specific to OpenSSL.
 
-### OpenSSL Options
+### OpenSSL options
 
 <table>
   <tr>
@@ -3325,7 +3325,7 @@ the `crypto`, `tls`, and `https` modules and are generally specific to OpenSSL.
   </tr>
 </table>
 
-### OpenSSL Engine Constants
+### OpenSSL engine constants
 
 <table>
   <tr>
@@ -3378,7 +3378,7 @@ the `crypto`, `tls`, and `https` modules and are generally specific to OpenSSL.
   </tr>
 </table>
 
-### Other OpenSSL Constants
+### Other OpenSSL constants
 
 <table>
   <tr>
@@ -3458,7 +3458,7 @@ the `crypto`, `tls`, and `https` modules and are generally specific to OpenSSL.
   </tr>
 </table>
 
-### Node.js Crypto Constants
+### Node.js crypto constants
 
 <table>
   <tr>
@@ -3528,7 +3528,7 @@ the `crypto`, `tls`, and `https` modules and are generally specific to OpenSSL.
 [AEAD algorithms]: https://en.wikipedia.org/wiki/Authenticated_encryption
 [CCM mode]: #crypto_ccm_mode
 [Caveats]: #crypto_support_for_weak_or_compromised_algorithms
-[Crypto Constants]: #crypto_crypto_constants_1
+[Crypto constants]: #crypto_crypto_constants_1
 [HTML 5.2]: https://www.w3.org/TR/html52/changes.html#features-removed
 [HTML5's `keygen` element]: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/keygen
 [NIST SP 800-131A]: https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-131Ar1.pdf