doc: tidy AssertionError text

Several minor improvements to text. Remove some repetition.

PR-URL: #28255
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

Author: Trott

doc/api/assert.md

@@ -21,33 +21,26 @@ thrown by the `assert` module will be instances of the `AssertionError` class.
 added: v0.1.21
 -->
 * `options` {Object}
-  * `message` {string} If provided, the error message is going to be set to this
-    value.
-  * `actual` {any} The `actual` property on the error instance is going to
-    contain this value. Internally used for the `actual` error input in case
-    e.g., [`assert.strictEqual()`] is used.
-  * `expected` {any} The `expected` property on the error instance is going to
-    contain this value. Internally used for the `expected` error input in case
-    e.g., [`assert.strictEqual()`] is used.
-  * `operator` {string} The `operator` property on the error instance is going
-    to contain this value. Internally used to indicate what operation was used
-    for comparison (or what assertion function triggered the error).
-  * `stackStartFn` {Function} If provided, the generated stack trace is going to
-    remove all frames up to the provided function.
+  * `message` {string} If provided, the error message is set to this value.
+  * `actual` {any} The `actual` property on the error instance.
+  * `expected` {any} The `expected` property on the error instance.
+  * `operator` {string} The `operator` property on the error instance.
+  * `stackStartFn` {Function} If provided, the generated stack trace omits
+    frames before this function.
 
 A subclass of `Error` that indicates the failure of an assertion.
 
 All instances contain the built-in `Error` properties (`message` and `name`)
 and:
 
-* `actual` {any} Set to the actual value in case e.g.,
-  [`assert.strictEqual()`] is used.
-* `expected` {any} Set to the expected value in case e.g.,
-  [`assert.strictEqual()`] is used.
+* `actual` {any} Set to the `actual` argument for methods such as
+  [`assert.strictEqual()`].
+* `expected` {any} Set to the `expected` value for methods such as
+  [`assert.strictEqual()`].
 * `generatedMessage` {boolean} Indicates if the message was auto-generated
   (`true`) or not.
-* `code` {string} This is always set to the string `ERR_ASSERTION` to indicate
-  that the error is actually an assertion error.
+* `code` {string} Value is always `ERR_ASSERTION` to show that the error is an
+  assertion error.
 * `operator` {string} Set to the passed in operator value.
 
 ```js