[#3307] Fix thanks to @xabbuh

(cherry picked from commit 38612bc)

Author: weaverryan

cookbook/security/entity_provider.rst

@@ -423,7 +423,7 @@ is set to 0, you won't be allowed.
 .. note::
 
     When using the ``AdvancedUserInterface``, you should also add any of
-    the properties used by these methods (like ``isActive``) to the ``serialize``
+    the properties used by these methods (like ``isActive()``) to the ``serialize()``
     method. If you *don't* do this, your user may not be deserialized correctly
     from the session on each request.