bpo-33641: Convert RFC references into links. (GH-7103)


85% of them are already links.
(cherry picked from commit 0a36ac1a09587735237c5978ebd046313922869c)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Doc/library/xmlrpc.client.rst b/Doc/library/xmlrpc.client.rst
index 390828e..ed2ccae 100644
--- a/Doc/library/xmlrpc.client.rst
+++ b/Doc/library/xmlrpc.client.rst
@@ -328,7 +328,7 @@
       Write the XML-RPC base 64 encoding of this binary item to the *out* stream object.
 
       The encoded data will have newlines every 76 characters as per
-      `RFC 2045 section 6.8 <https://tools.ietf.org/html/rfc2045#section-6.8>`_,
+      :rfc:`RFC 2045 section 6.8 <2045#section-6.8>`,
       which was the de facto standard base64 specification when the
       XML-RPC spec was written.