trust anchors: add KeyTag into comments

Fixes #167.
3 jobs for rr2str-pretty in 30 minutes and 22 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #5236
docker linux amd64
build:linux:amd64

00:11:51

 
  Test
passed #5238
docker linux amd64
deckard:linux:amd64

00:18:31

passed #5237
docker linux amd64
test:linux:amd64

00:17:30