Updated namespace

Author: Nyholm

messenger.rst

@@ -761,7 +761,7 @@ You can also configure AMQP-specific settings on your message by adding
 :class:`Symfony\\Component\\Messenger\\Transport\\AmqpExt\\AmqpStamp` to
 your Envelope::
 
-    use Symfony\Component\Messenger\Transport\AmqpExt\AmqpStamp;
+    use Symfony\Component\Messenger\Bridge\Amqp\Transport\AmqpStamp;
     // ...
 
     $attributes = [];