Merge branch '5.4' into 6.0

* 5.4:
  Update ExprBuilder.php

Author: fancyweb

src/Symfony/Component/Config/Definition/Builder/ExprBuilder.php

@@ -90,8 +90,10 @@ public function ifNull(): static
 
     /**
      * Tests if the value is empty.
+     *
+     * @return $this
      */
-    public function ifEmpty(): self
+    public function ifEmpty(): static
     {
         $this->ifPart = function ($v) { return empty($v); };