NativePromise template's to determine the type traits of the resolve/reject/settle methods are unable to deal with a lambda using `auto` for the type.

It causes a rather confusing, very long error message.

so you can't write something like:

using MyPromise = NativePromise<int, String>;
MyPromise::createAndSettle(workqueue, [] (auto&& result) {
});

you need to write:
MyPromise::createAndSettle(workqueue, [] (MyPromise::Result&& result) {
});

While it could be argued the latter is more readable and less prone to confusion, using `auto` everywhere is a rather popular trend within the WebKit team. So we should be able to deal with that if possible.