Unable to prove my keybase.pub site. (Underscore used in username/domain)

Errors when ever I add an underscore into the domain name, which prevents me from proving that I have control of https://spice_king.keybase.pub. Was just following along with @malgorithms did with his public folder, ended up finding this issue for my self. Effects both the linux keybase cli tool and the keybase.io website.

The keybase cli tool errors with `▶ ERROR Invalid hostname: spice_king.keybase.pub` while the site errors with a far less useful error:

Maybe as part of some kind of intro/initial profile setup you can get a new user to prove the ownership of their keybase.pub site. Just to help show how to get the ball rolling on things.

No source file or test is named. Reproduce the underscore case in the Linux CLI and keybase.io website, then trace the validation entry points; done means the intended behavior is established and both surfaces handle the case consistently with a useful result.

Written by the indexing model from the issue text.