Improve inline documentation for hooks in wp-admin/customize.php.

Props kpdesign.
Fixes #25444.

Built from https://develop.svn.wordpress.org/trunk@25858


git-svn-id: http://core.svn.wordpress.org/trunk@25770 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Rename the automatic_updates_send_email filter to auto_core_update_send_email. (Final name change.)

fixes #25653. Also:
 * Fully document all new hooks, methods, and classes in the upgrader.
 * Rename 'language' to 'translation' inside the upgrader.
 * Improve the readability of the crazy do-while loop in the is_vcs_checkout() method.

Built from https://develop.svn.wordpress.org/trunk@25859


git-svn-id: http://core.svn.wordpress.org/trunk@25771 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Inline documentation for the `WP_Date_Query` class in wp-includes/date.php.

- Adds a complete hash notation for the `WP_Date_Query` arguments array.
- Adds missing documentation for the `date_query_valid_columns` and `get_date_sql` filter hooks.

Props aeg0125 for the incremental patches.
Fixes #25552.

Built from https://develop.svn.wordpress.org/trunk@25860


git-svn-id: http://core.svn.wordpress.org/trunk@25772 1a063a9b-81f0-0310-95a4-ce76da25c4cd