Convert all configs to use new "error" style

[feross]

Right now our configs do this:

{
  "rule-name": 2
}

But this can be rewritten to:

{
  "rule-name": "error"
}

The latter is more readable.

[dcousens]

Agreed

[joshuacolvin]

I can take this one.

[feross]

@joshuacolvin Actually, I think I should take this one, if you haven't started it yet. There are some pending rule change PRs that I need to merge for v9. They won't apply cleanly if we change every line of the config first. Hopefully you haven't started this yet.

[joshuacolvin]

No worries! I haven't started yet.

[feross]

This is now resolved.