Rewrite dangling links to llvm/llvm-bugzilla-archive repo

[asl]

There are dangling references to llvm/llvm-bugzilla-archive repo, see e.g. #47280 We need to decide how to proceed with them and what is the best strategy for post-migration rewrite

[nikic]

Is there any chance that GitHub can make these work, in the sense that they get auto-linked and then follow the redirect?

[asl]

@nikic They are investigating whether they can fix it