Backport source links from 3.x.
Existing links have been updated to use the new reST role. In some
files, I have also made cosmetic changes to the header.
diff --git a/Doc/library/pickletools.rst b/Doc/library/pickletools.rst
index ea16190..ce47c97 100644
--- a/Doc/library/pickletools.rst
+++ b/Doc/library/pickletools.rst
@@ -8,6 +8,10 @@
.. versionadded:: 2.3
+**Source code:** :source:`Lib/pickletools.py`
+
+--------------
+
This module contains various constants relating to the intimate details of the
:mod:`pickle` module, some lengthy comments about the implementation, and a few
useful functions for analyzing pickled data. The contents of this module are