Manually mark comments as "outdated" in pull request (BB-8303)

I'm requesting the ability to mark inline comments as outdated manually, as we have workflows where comments are made to one section of code which actually require a fix in another section of code. We'd prefer to manually mark the comment as addressed/outdated even if the LOC in question wasn't modified by any commit.

The current workaround is to just reply to the message with a "fixed" or something to that effect, which we'd do anyway, but after a long review with many of these, the inline code gets polluted with many stale comments. Deleting is not desirable as we'd like an audit trail of the comments made.

Thanks