Merge branch '5.1'

* 5.1:
  [Messenger] Update messenger.rst

Author: javiereguiluz

messenger.rst

@@ -254,7 +254,7 @@ transport and its handler(s) will *not* be called immediately. Any messages not
 matched under ``routing`` will still be handled immediately.
 
 You can also route classes by their parent class or interface. Or send messages
-to multiple transport:
+to multiple transports:
 
 .. configuration-block::