Quotes: resType of MethodTypes (and others) can be a ByName type

[abgruszecki]

What it says in the title.

Suggested solution is to give up on the ByName name and just call it an ExprType.

For ergonomics, we may also want to consider always calling .widenExpr in .resType, and exposing a .preciseResType method that doesn't do so.

[abgruszecki]

/cc @BarkingBad this is the issue for the ByName type thing, you can see the resolution above.