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/cgi.rst b/Doc/library/cgi.rst
index 149cf23..b95f131 100644
--- a/Doc/library/cgi.rst
+++ b/Doc/library/cgi.rst
@@ -13,6 +13,10 @@
single: URL
single: Common Gateway Interface
+**Source code:** :source:`Lib/cgi.py`
+
+--------------
+
Support module for Common Gateway Interface (CGI) scripts.
This module defines a number of utilities for use by CGI scripts written in