Consider catching thrown errors from validators

We currently do not catch thrown errors from validators since it is expected that you return an Error instead.

This is by design and is fine. It may be worth handling uncaught exceptions too, though, just so the CLI gracefully fails validation rather than exiting.

this is the validation implementor's fault at the end of the day, if it happens, but covering it up could give better DX.

thoughts?

the negative is that it could cover up unintentional errors. today it'll be very obvious the validator has a bug and that wouldn't be the case anymore.