Add docs to the woefully under-documented `get_pages()`.

Props DrewAPicture.
Fixes #25186.


Built from https://develop.svn.wordpress.org/trunk@25266


git-svn-id: http://core.svn.wordpress.org/trunk@25232 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fourteen: further styling for medialement players, props iamtakashi. Fixes #25209.
Built from https://develop.svn.wordpress.org/trunk@25267


git-svn-id: http://core.svn.wordpress.org/trunk@25233 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix spacing in docs for `get_pages()`.

Props DrewAPicture.
See #25186.


Built from https://develop.svn.wordpress.org/trunk@25268


git-svn-id: http://core.svn.wordpress.org/trunk@25234 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Move `get_meta_type()` into the `WP_Meta_Query` class as `get_cast_for_type()`. `WP_Query` can then access it like: `$this->meta_query->get_cast_for_type()`.

See #21621, [25255].


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git-svn-id: http://core.svn.wordpress.org/trunk@25235 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Simplify the check for false-y `child_of` arg.

Props SergeyBiryukov.
See #25230, [25245].


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git-svn-id: http://core.svn.wordpress.org/trunk@25236 1a063a9b-81f0-0310-95a4-ce76da25c4cd