Merge branch '3.4' into 4.3

* 3.4:
  [Yaml] Implement multiline string as scalar block for tagged values
  [HttpFoundation] Use `Cache-Control: must-revalidate` only if explicit lifetime has been given
  [FrameworkBundle] Use UserInterface to @return in getUser method
  [CI] Replace php7.4snapshot with php7.4 in Travis configuration
  [ExpressionLanguage][Node][BinaryNode] Process division by zero
  forward caught exception
  [Validator][ConstraintValidator] Stop passing unnecessary timezone argument to \DateTime
  add tags before processing them
  [MonologBridge] Fix debug processor datetime type

Author: nicolas-grekas

Controller/ControllerTrait.php

@@ -30,6 +30,7 @@
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
 use Symfony\Component\Security\Core\Exception\AccessDeniedException;
+use Symfony\Component\Security\Core\User\UserInterface;
 use Symfony\Component\Security\Csrf\CsrfToken;
 use Symfony\Component\WebLink\EventListener\AddLinkHeaderListener;
 
@@ -351,7 +352,7 @@ protected function getDoctrine(): ManagerRegistry
     /**
      * Get a user from the Security Token Storage.
      *
-     * @return object|null
+     * @return UserInterface|object|null
      *
      * @throws \LogicException If SecurityBundle is not available
      *