[Messenger] Mention ScheduledStamp

Author: alexandre-daubois

components/messenger.rst

@@ -162,6 +162,15 @@ Here are some important envelope stamps that are shipped with the Symfony Messen
   to configure the validation groups used when the validation middleware is enabled.
 * :class:`Symfony\\Component\\Messenger\\Stamp\\ErrorDetailsStamp`,
   an internal stamp when a message fails due to an exception in the handler.
+* :class:`Symfony\\Component\\Messenger\\Stamp\\ScheduledStamp`,
+  a stamp that marks the message as produced by a scheduler. You can learn
+  more about it in the :doc:`Scheduler component page </scheduler>`. This helps
+  differentiate from messages created "manually".
+
+.. versionadded:: 6.4
+
+    The :class:`Symfony\\Component\\Messenger\\Stamp\\ScheduledStamp` was
+    introduced in Symfony 6.4.
 
 .. note::
 

scheduler.rst

@@ -914,6 +914,15 @@ before being further redispatched to its corresponding handler::
         }
     }
 
+When using the ``RedispatchMessage``, a
+:class:`Symfony\\Component\\Messenger\\Stamp\\ScheduledStamp` will be attached
+to the message, helping you identify those messages when needed.
+
+.. versionadded:: 6.4
+
+    Automatically attaching a :class:`Symfony\\Component\\Messenger\\Stamp\\ScheduledStamp`
+    to redispatched messages was introduced in Symfony 6.4.
+
 .. _`Memoizing`: https://en.wikipedia.org/wiki/Memoization
 .. _`cron command-line utility`: https://en.wikipedia.org/wiki/Cron
 .. _`crontab.guru website`: https://crontab.guru/