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/optparse.rst b/Doc/library/optparse.rst
index 39a44bd..cb78b83 100644
--- a/Doc/library/optparse.rst
+++ b/Doc/library/optparse.rst
@@ -4,17 +4,18 @@
 .. module:: optparse
    :synopsis: Command-line option parsing library.
    :deprecated:
+.. moduleauthor:: Greg Ward <gward@python.net>
+.. sectionauthor:: Greg Ward <gward@python.net>
+
+.. versionadded:: 2.3
 
 .. deprecated:: 2.7
    The :mod:`optparse` module is deprecated and will not be developed further;
    development will continue with the :mod:`argparse` module.
 
-.. moduleauthor:: Greg Ward <gward@python.net>
+**Source code:** :source:`Lib/optparse.py`
 
-.. versionadded:: 2.3
-
-.. sectionauthor:: Greg Ward <gward@python.net>
-
+--------------
 
 :mod:`optparse` is a more convenient, flexible, and powerful library for parsing
 command-line options than the old :mod:`getopt` module.  :mod:`optparse` uses a