minor #19699 [Messenger] Messenger: custom consumer name with systemd (maxxer)

This PR was submitted for the 7.0 branch but it was merged into the 6.4 branch instead.

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[Messenger] Messenger: custom consumer name with systemd

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dd69e53 Messenger: custom consumer name with systemd

Author: javiereguiluz

messenger.rst

@@ -814,6 +814,8 @@ directory. For example, you can create a new ``messenger-worker.service`` file.
 
     [Service]
     ExecStart=php /path/to/your/app/bin/console messenger:consume async --time-limit=3600
+    # For Redis, set a custom consumer name for each instance
+    Environment="MESSENGER_CONSUMER_NAME=symfony-%n-%i"
     Restart=always
     RestartSec=30