DOC: add note about downloading helper library

tacaswell · tacaswell · commit add5a589e071 · 2017-06-09T00:18:00.000-07:00
diff --git a/examples/event_handling/pong_sgskip.py b/examples/event_handling/pong_sgskip.py
@@ -5,6 +5,10 @@
 
 A small game demo using Matplotlib.
 
+.. only:: builder_html
+
+   This example requires :download:`pipong.py <pipong.py>`
+
 """
 from __future__ import print_function, division
 import time
