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-0.5.0.rst b/docs/release-notes/release-notes-0.5.0.rst
index b81f209..914c5de 100644
--- a/docs/release-notes/release-notes-0.5.0.rst
+++ b/docs/release-notes/release-notes-0.5.0.rst
@@ -112,8 +112,7 @@
   ``ndn::CertificateExtension``, ``ndn::CertificateSubjectDescription``.  When necessary, use
   ``security::v1::PublicKey``, ``security::v1::Certificate``, ``security::v1::IdentityCertificate``,
   ``security::v1::CertificateExtension``, ``security::v1::CertificateSubjectDescription`` instead.
-  The next release will feature :doc:`a new version of NDN Certificate format
-  <../specs/certificate-format>`.
+  The next release will feature :doc:`a new version of the NDN Certificate format </specs/certificate>`.
 
 Removed
 ^^^^^^^