Docs: Add a file header to wp-includes/class-wp-role.php, introduced in [33752].

Also adjusts the class DocBlock for `WP_Role`.

See #33413. See #33701.


git-svn-id: https://develop.svn.wordpress.org/trunk@34395 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-role.php

@@ -1,10 +1,16 @@
 <?php
 /**
- * WordPress Role class.
+ * User API: WP_Role class
  *
- * @since 2.0.0
  * @package WordPress
  * @subpackage User
+ * @since 4.4.0
+ */
+
+/**
+ * Core class used to extend the user roles API.
+ *
+ * @since 2.0.0
  */
 class WP_Role {
 	/**