Assume the user is using Flex when deploying

Author: royklutman

deployment.rst

@@ -157,7 +157,7 @@ as you normally do:
 .. caution::
 
     If you get a "class not found" error during this step, you may need to
-    run ``export SYMFONY_ENV=prod`` (or ``export APP_ENV=prod`` if you're
+    run ``export APP_ENV=prod`` (or ``export SYMFONY_ENV=prod`` if you're not
     using :doc:`Symfony Flex </setup/flex>`) before running this command so
     that the ``post-install-cmd`` scripts run in the ``prod`` environment.