Add ergonomic way to allow recovery steps to be part of the logger.warn / error

@kenotron 2019-05-23 05:39:39发表于 microsoft/just

@kevinclement suggestion:

Since you're including logging at part of the framework, it would be nice if it had an easy way to make errors 'pretty', or 'sane' or 'actionable'. [...] map some ridiculous error message into a human readable error, or some error with context. e.g. invalid token. Would be cool if there were a nice ergonomic way to map those cleanly. Could be at the task level or some uber catch.