[Messenger] Merge several short articles into the main Messenger article

Author: javiereguiluz

_build/redirection_map

@@ -562,3 +562,6 @@
 /frontend/assetic/index /frontend
 /controller/argument_value_resolver /controller/value_resolver
 /frontend/ux https://symfony.com/bundles/StimulusBundle/current/index.html
+/messenger/handler_results /messenger#messenger-getting-handler-results
+/messenger/dispatch_after_current_bus /messenger#messenger-transactional-messages
+/messenger/multiple_buses /messenger#messenger-multiple-buses

components/messenger.rst

@@ -146,7 +146,7 @@ Here are some important envelope stamps that are shipped with the Symfony Messen
    to delay handling of an asynchronous message.
 #. :class:`Symfony\\Component\\Messenger\\Stamp\\DispatchAfterCurrentBusStamp`,
    to make the message be handled after the current bus has executed. Read more
-   at :doc:`/messenger/dispatch_after_current_bus`.
+   at :ref:`messenger-transactional-messages`.
 #. :class:`Symfony\\Component\\Messenger\\Stamp\\HandledStamp`,
    a stamp that marks the message as handled by a specific handler.
    Allows accessing the handler returned value and the handler name.