General: Use static on closures whenever $this is not used to avoid memory leaks.

Props westonruter, jrf, spacedmonkey.
Fixes #58323.


git-svn-id: https://develop.svn.wordpress.org/trunk@55822 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/kses.php

@@ -1177,7 +1177,7 @@ function wp_kses_attr( $element, $attr, $allowed_html, $allowed_protocols ) {
 	// Check if there are attributes that are required.
 	$required_attrs = array_filter(
 		$allowed_html[ $element_low ],
-		function( $required_attr_limits ) {
+		static function( $required_attr_limits ) {
 			return isset( $required_attr_limits['required'] ) && true === $required_attr_limits['required'];
 		}
 	);