Fixed verb "send" in past tense: "sent"

Author: leoloso

notifier.rst

@@ -15,7 +15,7 @@ Installation
 Current web applications use many different channels to send messages to
 the users (e.g. SMS, Slack messages, emails, push notifications, etc.). The
 Notifier component in Symfony is an abstraction on top of all these
-channels. It provides a dynamic way to manage how the messages are send.
+channels. It provides a dynamic way to manage how the messages are sent.
 Get the Notifier installed using:
 
 .. code-block:: terminal