Alter some text for clarity on the Media Settings page.

Props layotte, DrewAPicture.
Fixes #15732.


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git-svn-id: http://core.svn.wordpress.org/trunk@25472 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add `@access private` to `_get_custom_object_labels()`, which was already implied by the dangling underscore. Cast `$labels` to `array` in `get_taxonomy_labels()` and `_get_custom_object_labels()`.

Props nacin, foofy.
Fixes #16310.


Built from https://develop.svn.wordpress.org/trunk@25553


git-svn-id: http://core.svn.wordpress.org/trunk@25473 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add hooks to `wp_count_posts()`. Adds filter docs. Adds unit test to test `count_posts` filter.

Props nacin, DrewAPicture. 
Fixes #16603.


Built from https://develop.svn.wordpress.org/trunk@25554


git-svn-id: http://core.svn.wordpress.org/trunk@25474 1a063a9b-81f0-0310-95a4-ce76da25c4cd