Cross-reference `WP_Comment_Query::query()` as the location for finding information on default arguments for `WP_Comment_Query`.

Also updates the return types on `get_comments()` and `get_approved_comments()`, as an integer can also be returned if the `$count` argument is true.

Fixes #30111.


git-svn-id: https://develop.svn.wordpress.org/trunk@30281 602fd350-edb4-49c9-b593-d223f7449a82