Inline documentation cleanup in wp-includes/comment-template.php.

This cleanup follows [25567] and brings the docs in-line with standards that at the time had not yet been finalized.

These changes include
* Moving in-line `@see` tags to their own lines
* Using docs-specific variables in hook docs
* Fixing line-wrapping throughout
* Typos and punctuation
* Converting hash notation values to variables per the standard

Fixes #27083. See #20495.


git-svn-id: https://develop.svn.wordpress.org/trunk@27156 602fd350-edb4-49c9-b593-d223f7449a82