Corrected typo in notifier.rst

Replaced "send" by "sent".

Author: askeita

notifier.rst

@@ -615,7 +615,7 @@ The
 :class:`Symfony\\Component\\Notifier\\Notification\\SmsNotificationInterface`
 and
 :class:`Symfony\\Component\\Notifier\\Notification\\EmailNotificationInterface`
-also exists to modify messages send to those channels.
+also exists to modify messages sent to those channels.
 
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