Fix typo in mailer.rst

Author: norival

mailer.rst

@@ -1752,7 +1752,7 @@ FailedMessageEvent
 
     The ``FailedMessageEvent`` event was introduced in Symfony 6.2.
 
-``FailedMessageEvent`` allows acting on the the initial message in case of a failure::
+``FailedMessageEvent`` allows acting on the initial message in case of a failure::
 
     use Symfony\Component\EventDispatcher\EventSubscriberInterface;
     use Symfony\Component\Mailer\Event\FailedMessageEvent;