appview issues doesn't show when a PR referenced it #430

when you go to an issue, say https://tangled.org/tangled.org/core/issues/400

you will see that it's referenced by https://tangled.org/did:plc:wshs7t2adsemcrrd4snkeqli/core/pulls/1054, but you can not know when it was actually referenced. I think adding a line that says "vixalien mentioned in #1054" with a date or something between the comment threads would be nice. same as github