Add missing doc blocks to wp-admin/includes/*.

Fix some egregious uses of tabbing.
Some functions can simply return `apply_filters(...)` instead of setting a variable that is immediately returned.

See #32444.


git-svn-id: https://develop.svn.wordpress.org/trunk@32654 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-wp-filesystem-base.php

@@ -171,7 +171,6 @@ class WP_Filesystem_Base {
 	 * @return string|false The location of the remote path, false on failure.
 	 */
 	public function find_folder( $folder ) {
-
 		if ( isset( $this->cache[ $folder ] ) )
 			return $this->cache[ $folder ];