Fixup code example.

tannewt · tannewt · commit 10d501f35253 · 2017-05-04T11:44:55.000-07:00
diff --git a/README.rst b/README.rst
@@ -26,7 +26,10 @@ This is easily achieved by downloading
 Usage Example
 =============
 
-This plays Frosty the Snowman::
+This plays Frosty the Snowman:
+
+.. code-block: python
+
     import board
     import adafruit_rtttl
 
