Added a learn more section

Author: Nyholm

components/messenger.rst

@@ -195,6 +195,14 @@ It will wrap the received messages into ``ReceivedMessage`` objects and the
 ``SendMessageMiddleware`` middleware will know it should not route these
 messages again to a transport.
 
+Learn More
+----------
+
+.. toctree::
+:maxdepth: 1
+      :glob:
+
+      /messenger
 
 .. _blog posts about command buses: https://matthiasnoback.nl/tags/command%20bus/
 .. _SimpleBus project: http://simplebus.io