Keybase revoke-sig site command example doesn't work in Go client (1.0.5-0)

When trying to abandon an incomplete proof on my profile page I'm instructed to run `keybase revoke-sig [sig]`. Running this with the latest homebrewed Go client returns `No help topic for 'revoke-sig'`.

I searched for other reports before posting this, hopefully it's not a dupe.

Start by reproducing `keybase revoke-sig [sig]` with the Go client and checking the profile-page instruction that references it. Trace the client entry point for the missing help topic and verify how an incomplete proof is abandoned. Done means the documented command and client behavior agree.

Written by the indexing model from the issue text.