Part II of inline documentation for hooks in wp-includes/post.php.

Documents all remaining hooks following [28041] and [28042]. Also updates the hash notation style for `wp_insert_post()`.

Props nacin for several hook descriptions.

Fixes #25376.

Built from https://develop.svn.wordpress.org/trunk@28106


git-svn-id: http://core.svn.wordpress.org/trunk@27937 1a063a9b-81f0-0310-95a4-ce76da25c4cd