Reword comment in setup.cfg

Author: pfmoore

setup.cfg

@@ -1,5 +1,6 @@
 [bdist_wheel]
-# This flag says that the code is written to work on both Python 2 and Python
-# 3. If at all possible, it is good practice to do this. If you cannot, you
-# will need to generate wheels for each Python version that you support.
+# This flag says to generate wheels that support both Python 2 and Python
+# 3. If your code will not run unchanged on both Python 2 and 3, you will
+# need to generate separate wheels for each Python version that you
+# support.
 universal=1