Add "Reply to comment" button to all comments, auto-mention the author of that comment

Problem to solve

Keeping track of conversations in comments can be difficult at times if the replies don't mention your username, as you won't receive a todo item. Some people have gotten around this by saying stuff like "Remember to @ me" in their statuses, but this feels like something that should be a feature.

Proposal

Currently we only show the "Reply to comment" button on the top-level comment in a chain, e.g.

If we add this button to all comments, we could then have it auto-mention the author of that comment at the start of the reply, e.g. @robotmay ..., which would help people keep track of replies to their comments better (as it would create a todo). The default reply field at the bottom could stay as-is, not auto-mentioning anybody.

Permissions and Security

Documentation

Availability & Testing

What does success look like, and how can we measure that?

What is the type of buyer?

Links / references