Ref manual fix

Author: jrobinAV

taipy/event/event_processor.py

@@ -99,7 +99,7 @@ def on_scenario(event: Event, gui: Gui):
             if __name__ == "__main__":
                 event_processor = EventProcessor()
                 event_processor.on_event(callback=on_entity_creation, operation=EventOperation.CREATION)
-                event_processor.on_event(callback=scenario_event, entity_type=EventEntityType.SCENARIO)
+                event_processor.on_event(callback=on_scenario, entity_type=EventEntityType.SCENARIO)
                 event_processor.start()
             ```