documentation: add important information about attributes parameter (#18732)

If the attributes aren't set in the right order the module always detect
an attributes change.

lib/ansible/utils/module_docs_fragments/files.py

@@ -75,6 +75,7 @@ options:
   attributes:
     description:
       - Attributes of the file or directory should be. To get supported flags look at the man page for I(chattr) on the taget system.
+        This string should contain the attributes in the same order than they are displayed by I(lsattr).
     required: false
     default: None
     aliases: ['attr']