Docs: Add missing parameter and return descriptions to the DocBlock for `WP_Rewrite::iis7_url_rewrite_rules()`.

See #32246.


git-svn-id: https://develop.svn.wordpress.org/trunk@35941 602fd350-edb4-49c9-b593-d223f7449a82

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

@@ -1552,7 +1552,9 @@ class WP_Rewrite {
 	 * @since 2.8.0
 	 * @access public
 	 *
-	 * @return string
+	 * @param bool $add_parent_tags Optional. Whether to add parent tags to the rewrite rule sets.
+	 *                              Default false.
+	 * @return string IIS7 URL rewrite rule sets.
 	 */
 	public function iis7_url_rewrite_rules( $add_parent_tags = false ) {
 		if ( ! $this->using_permalinks() )