Clarify documentation for hooks in `sanitize_post_field()`.

* `edit_post_{$field}` pairs with `edit_{$field}`
* `pre_post_{$field}` pairs with `pre_{$field}`
* `post_{$field}` pairs with `{$field}`

As the above pairs' docs are unnecessarily duplicative, the second sets of docs have been removed. Also, the "duplicates" are purposely not marked as such in this case as the hook names differ. Also remove `@deprecated` tags mistakenly left in in [28041].

See #25376.

Built from https://develop.svn.wordpress.org/trunk@28042


git-svn-id: http://core.svn.wordpress.org/trunk@27872 1a063a9b-81f0-0310-95a4-ce76da25c4cd