Administration: Add missing description for "Page title" element of the admin menu array.

Props ajoah, valentinbora, kaitlin414.
Fixes #42911.
Built from https://develop.svn.wordpress.org/trunk@47434


git-svn-id: http://core.svn.wordpress.org/trunk@47221 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/menu.php

@@ -10,12 +10,13 @@
  * Constructs the admin menu.
  *
  * The elements in the array are:
- *     0: Menu item name
+ *     0: Menu item name.
  *     1: Minimum level or capability required.
- *     2: The URL of the item's file
- *     3: Class
- *     4: ID
- *     5: Icon for top level menu
+ *     2: The URL of the item's file.
+ *     3: Page title.
+ *     4: Classes.
+ *     5: ID.
+ *     6: Icon for top level menu.
  *
  * @global array $menu
  */

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-alpha-47433';
+$wp_version = '5.5-alpha-47434';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.