docs: clarify and cleanup the certificate format spec

Also, cleanup references to the legacy signed interest spec

Change-Id: Ib761399b6e44cefea6331e4e128bb2976c2fc11d
diff --git a/docs/release-notes/release-notes-0.6.0.rst b/docs/release-notes/release-notes-0.6.0.rst
index 4beb3ef..c2e045f 100644
--- a/docs/release-notes/release-notes-0.6.0.rst
+++ b/docs/release-notes/release-notes-0.6.0.rst
@@ -16,7 +16,7 @@
   interfaces. At the same time, management APIs for :ndn-cxx:`ValidatorConfig` remained
   intact; transition to the new framework would require only adjusting
   :ndn-cxx:`Validator::validate` calls and updating configuration files to follow the new
-  naming conventions of :ref:`NDN Certificate Format Version 2.0`.
+  naming conventions of :doc:`/specs/certificate`.
 
 - Integration of fetching certificates using Certificate Bundle as part of specialized
   ``CertificateFetcher`` (:issue:`3891`)