Merge branch '5.1' into 5.2

* 5.1:
  [Event Dispatcher] Fix typo for __invoke()

Author: javiereguiluz

event_dispatcher.rst

@@ -122,7 +122,7 @@ listener class:
    the ``kernel.exception`` event);
 #. If that method is not defined either, try to call the ``__invoke()`` magic
    method (which makes event listeners invokable);
-#. If the ``_invoke()`` method is not defined either, throw an exception.
+#. If the ``__invoke()`` method is not defined either, throw an exception.
 
 .. note::