Inline documentation for the following filter hooks in wp-includes/pluggable.php:
* `comment_notification_recipients`
* `comment_notification_notify_author`

Also removes some generic `@uses` tags from various related doc blocks.

Props markjaquith.
Fixes #25699.


git-svn-id: https://develop.svn.wordpress.org/trunk@26388 602fd350-edb4-49c9-b593-d223f7449a82