Users (who aren't whitelisted) who post top-level to an proposal should have their comment automatically moved to a PR review comment

The Spec Core Team often has the manual task of cleaning up comments that appear from contributors at the top-level of the MSC (a PR comment, rather than a PR review comment). Cleaning them up involves copying the contents of the comment, hiding it, then starting a new thread on the MSC (typically at line 1) and pasting the contents there as a quote. Along with some text to inform the user as to why it was necessary.

This is time-consuming manual work. And sometimes when we don't catch these comments quickly enough, other people will reply with another top-level comment, making the problem worse.

It would be nice if mscbot could take care of doing that automatically, along with a canned explanation. It should support a config option that excludes certain users (SCT, guardians, MSC author) who occasionally do need to post top-level from the correction.

No file, test, or entry point is named in the issue. Start by locating the code that handles GitHub pull-request comments and configuration, then trace how top-level comments and user exclusions are represented. Done means eligible comments are moved into review threads with the canned explanation while excluded users are unaffected.

Written by the indexing model from the issue text.