C++: Add documentation for the LineComment class

cpp/ql/test/TestUtilities/InlineExpectationsTestPrivate.qll

@@ -2,14 +2,22 @@ import cpp
 
 private newtype TLineComment = MkLineComment(CppStyleComment c)
 
+/**
+ * Represents a line comment in the CPP style.
+ * Unlike the `CppStyleComment` class, however, the string returned by `getContents` does _not_
+ * include the preceding comment marker (`//`).
+ */
 class LineComment extends TLineComment {
   CppStyleComment comment;
 
   LineComment() { this = MkLineComment(comment) }
 
+  /** Returns the contents of the given comment, _without_ the preceding comment marker (`//`). */
   string getContents() { result = comment.getContents().suffix(2) }
 
+  /** Gets a textual representation of this element. */
   string toString() { result = comment.toString() }
 
+  /** Gets the location of this comment. */
   Location getLocation() { result = comment.getLocation() }
 }