Add ability to pin comments in really long issue threads

[danny-andrews]

There are some issues which have been solved for a long time, but the threads are so long that people have a difficult time finding the solution. Leaving a final comment and closing the discussion works, but feels heavy-handed and prevents people from adding more info/voicing confusion over the proposed solution. It would be nice for collabs to have a way to pin a comment which is the "tried-and-true" way to solve a certain issue.

[cirosantilli]

Possible alternative: sort comments by upvote: #601

Current workaround: edit the post description

[danny-andrews]

Current workaround: edit the post description

That's a nice workaround. I like it.