`operator co_await` as TRY operator

Many people have requested that operator co_await be overloaded to behave as a TRY operator when supplied with an Outcome type. Outcome does not implement that extension, nor will we accept PRs contributing support for this. We think you should use OUTCOME_CO_TRY() as this will lead to more maintainable and future proof code. However, we deliberately do not get in the way of you implementing that overload yourself in your own Outcome-based code. »