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/smtplib.rst b/Doc/library/smtplib.rst
index d59ebf7..b0b58e8 100644
--- a/Doc/library/smtplib.rst
+++ b/Doc/library/smtplib.rst
@@ -1,4 +1,3 @@
-
:mod:`smtplib` --- SMTP protocol client
=======================================
@@ -11,6 +10,10 @@
pair: SMTP; protocol
single: Simple Mail Transfer Protocol
+**Source code:** :source:`Lib/smtplib.py`
+
+--------------
+
The :mod:`smtplib` module defines an SMTP client session object that can be used
to send mail to any Internet machine with an SMTP or ESMTP listener daemon. For
details of SMTP and ESMTP operation, consult :rfc:`821` (Simple Mail Transfer