[Pitch] Issue Handling Traits

[smontgomery (Stuart Montgomery)]

@x-sheep

On that note, I wouldn't mind if some issue kinds weren't passed through this new handler. Expectation failures and thrown errors from user space are the most important for my case, and other library errors should probably be preserved and shown as-is.

Of the current set of issue "kinds" (enumerated in Issue.Kind), only one strikes me as something we might want to omit from this interface: .system. The others generally do stem from something which is under the users' control. In general, I think it's a reasonable suggestion that only issues which may somehow be caused by a user should be included, so I'll incorporate this suggestion into the proposal.