(If) there are old comments tagged to issues that have been closed, remove the comments. E.g., at time of writing, there are some comments tagged to comb_utils issue 24 that can be deleted.

Watch out for comments that are tagged to issues that were closed as duplicates or otherwise replaced or moved and somehow unresolved. In that case, just update the tag to point to the correct issue. E.g., at time of writing, there's a comment tagged to bfb_delivery issue 61, which is closed as a duplicate of comb_utils issue. We'd want to leave the comment, but update it to point to the comb_utils issue.