Use the right diff header.

 - Legacy-Id: 526

Author: fenner

test/diff/_idtracker_12689_

@@ -1,5 +1,5 @@
 --- https://datatracker.ietf.org/public/pidtracker.cgi?command=view_id&dTag=12689&rfc_flag=0 
-+++ /idtracker/draft-ietf-isis-link-attr/ 
++++ /idtracker/12689/ 
 @@ -40,2 +40,3 @@
 -This draft is basically ready for publication, but has nits and more
 -...