Improve the `@param` docs for `src/includes/theme.php` and `src/includes/update.php`.

See #30224.

Built from https://develop.svn.wordpress.org/trunk@30672


git-svn-id: http://core.svn.wordpress.org/trunk@30662 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Improve various `@param` docs.

See #30224.

Built from https://develop.svn.wordpress.org/trunk@30673


git-svn-id: http://core.svn.wordpress.org/trunk@30663 1a063a9b-81f0-0310-95a4-ce76da25c4cd