Merge branch '4.3' into 4.4

* 4.3:
  cs fix
  Fix return statements
  [TwigBridge] add missing dep
  Add false type to ChoiceListFactoryInterface::createView $label argument
  Update UPGRADE guide of 4.3 for EventDispatcher
  [SecurityBundle] display the correct class name on the deprecated notice

Author: nicolas-grekas

Constraints/Regex.php

@@ -82,7 +82,7 @@ public function getHtmlPattern()
 
         // Quit if delimiters not at very beginning/end (e.g. when options are passed)
         if ($this->pattern[0] !== $this->pattern[\strlen($this->pattern) - 1]) {
-            return;
+            return null;
         }
 
         $delimiter = $this->pattern[0];