doc: clarify node.js addons language

doc/api/_toc.md

@@ -7,7 +7,7 @@
 
 * [Assertion Testing](assert.html)
 * [Buffer](buffer.html)
-* [C/C++ Addons](addons.html)
+* [C++ Addons](addons.html)
 * [C/C++ Addons - N-API](n-api.html)
 * [Child Processes](child_process.html)
 * [Cluster](cluster.html)

doc/api/addons.md

@@ -1,6 +1,6 @@
-# C/C++ Addons
+# C++ Addons
 
-Node.js Addons are dynamically-linked shared objects, written in C or C++, that
+Node.js Addons are dynamically-linked shared objects, written in C++, that
 can be loaded into Node.js using the [`require()`][require] function, and used
 just as if they were an ordinary Node.js module. They are used primarily to
 provide an interface between JavaScript running in Node.js and C/C++ libraries.
@@ -26,7 +26,7 @@ involving knowledge of several components and APIs :
    off-loading work via libuv to non-blocking system operations, worker threads
    or a custom use of libuv's threads.
 
- - Internal Node.js libraries. Node.js itself exports a number of C/C++ APIs
+ - Internal Node.js libraries. Node.js itself exports a number of C++ APIs
    that Addons can use — the most important of which is the
    `node::ObjectWrap` class.
 

doc/api/n-api.md

@@ -12,7 +12,7 @@ compiled for one version to run on later versions of Node.js without
 recompilation.
 
 Addons are built/packaged with the same approach/tools
-outlined in the section titled  [C/C++ Addons](addons.html).
+outlined in the section titled  [C++ Addons](addons.html).
 The only difference is the set of APIs that are used by the native code.
 Instead of using the V8 or [Native Abstractions for Node.js][] APIs,
 the functions available in the N-API are used.