Add changelog entries to the `post_gallery` and `post_playlist` hook docs for the `$instance` variable that was added in [31304].

Props ninnypants for the initial patch.
Fixes #31151.

Built from https://develop.svn.wordpress.org/trunk@31309


git-svn-id: http://core.svn.wordpress.org/trunk@31290 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/media.php

@@ -938,6 +938,7 @@ function gallery_shortcode( $attr ) {
 	 * the default gallery template.
 	 *
 	 * @since 2.5.0
+	 * @since 4.2.0 The `$instance` parameter was added.
 	 *
 	 * @see gallery_shortcode()
 	 *
@@ -1214,6 +1215,7 @@ function wp_playlist_shortcode( $attr ) {
 	 * of the default playlist output, returning the passed value instead.
 	 *
 	 * @since 3.9.0
+	 * @since 4.2.0 The `$instance` parameter was added.
 	 *
 	 * @param string $output   Playlist output. Default empty.
 	 * @param array  $attr     An array of shortcode attributes.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31308';
+$wp_version = '4.2-alpha-31309';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.