WIN_CLOSED bulk update. No more test for event is None, use WIN_CLOSED instead

DemoPrograms/Demo_Keyboard_Realtime.py

@@ -18,7 +18,7 @@ while True:
             print('%s - %s' % (event, ord(event)))
         else:
             print(event)
-    elif event is None:
+    elif event == sg.WIN_CLOSED:
         break
 
 window.close()