[Flex] Tell that var/logs/ directory was renamed

Author: phansys

setup/flex.rst

@@ -270,6 +270,9 @@ manual steps:
 #. Remove the ``bin/symfony_requirements`` script and if you need a replacement
    for it, use the new `Symfony Requirements Checker`_.
 
+#. Update entry for log directory at ``.gitignore`` and in any other place in order
+   to set ``var/log/``, which previously was ``var/logs/``.
+
 Customizing Flex Paths
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