docs: simplify conf.py and fix compatibility with upcoming Sphinx 6.0

Change-Id: Ia69db4e8d6bef7f779bd3556be6afe534df8ad31
diff --git a/docs/index.rst b/docs/index.rst
index 4bfa906..559b338 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -29,7 +29,7 @@
 Downloading
 -----------
 
-* `Source code git repository <https://github.com/named-data/NDNS>`_
+* `Source code git repository <https://github.com/named-data/ndns>`_
 
 License
 -------
@@ -37,4 +37,4 @@
 NDNS is an open and free software package licensed under GPL 3.0 license and is the
 centerpiece of our committement to making NDN's core technology open and free to all
 Internet users and developers. For more information about the licensing details and
-limitation, refer to `COPYING.md <https://github.com/named-data/NDNS/blob/master/COPYING.md>`_.
+limitation, refer to `COPYING.md <https://github.com/named-data/ndns/blob/master/COPYING.md>`_.