Reference the meta-discussions for PyPy and Python3 in the changelog. [skip ci]

changelog.rst

@@ -25,8 +25,8 @@ Unreleased
 
 - Add support for Python 3.3 and 3.4. Many people have contributed to
   this effort, including but not limited to Fantix King, hashstat,
-  Elizabeth Myers, jander, Luke Woydziak, and others.
-- Add support for PyPy.
+  Elizabeth Myers, jander, Luke Woydziak, and others. See :issue:`38`.
+- Add support for PyPy. See :issue:`248`.
 - Drop support for Python 2.5. Python 2.5 users can continue to use
   gevent 1.0.x.
 - Fix ``gevent.greenlet.joinall`` to not ignore ``count`` when