Fix the wp_count_attachments() PHPDoc to reflect that it returns an object, not array.

See #25412.


git-svn-id: https://develop.svn.wordpress.org/trunk@27807 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/post.php

@@ -2161,7 +2161,7 @@ function wp_count_posts( $type = 'post', $perm = '' ) {
  * @since 2.5.0
  *
  * @param string|array $mime_type Optional. Array or comma-separated list of MIME patterns.
- * @return array Number of posts for each mime type.
+ * @return object An object containing the attachment counts by mime type.
  */
 function wp_count_attachments( $mime_type = '' ) {
 	global $wpdb;