Add a description for the $data parameter in the DocBlock for the customize_save_response hook introduced in [31062].

Props westonruter.
Fixes #29098.


git-svn-id: https://develop.svn.wordpress.org/trunk@31063 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-customize-manager.php

@@ -677,7 +677,8 @@ final class WP_Customize_Manager {
 		 *
 		 * @since 4.2.0
 		 *
-		 * @param array $data
+		 * @param array                $data Additional information passed back to the 'saved'
+		 *                                   event on `wp.customize`.
 		 * @param WP_Customize_Manager $this WP_Customize_Manager instance.
 		 */
 		$response = apply_filters( 'customize_save_response', array(), $this );