Moving forwards on named function types

[madsmtm]

RFC 3476 was recently submitted, which contains many of the same desires as the draft RFC on named function types in this repo.

Would it be welcome if I opened a few PRs to that RFC text, to help move the initiative forwards? As an example of a change I'd make, I think it makes sense to talk about function item types instead of "function definitions" / "fndef", as the RFC text currently does.