Inline documentation for hooks in wp-includes/comment-template.php.

Fixes #25396.

Built from https://develop.svn.wordpress.org/trunk@25584


git-svn-id: http://core.svn.wordpress.org/trunk@25501 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Avoid a notice. see #14408, [25574].

Built from https://develop.svn.wordpress.org/trunk@25585


git-svn-id: http://core.svn.wordpress.org/trunk@25502 1a063a9b-81f0-0310-95a4-ce76da25c4cd