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/smtpd.rst b/Doc/library/smtpd.rst
index 2767516..ebb0b30 100644
--- a/Doc/library/smtpd.rst
+++ b/Doc/library/smtpd.rst
@@ -7,8 +7,9 @@
.. moduleauthor:: Barry Warsaw <barry@zope.com>
.. sectionauthor:: Moshe Zadka <moshez@moshez.org>
+**Source code:** :source:`Lib/smtpd.py`
-
+--------------
This module offers several classes to implement SMTP servers. One is a generic
do-nothing implementation, which can be overridden, while the other two offer