Investigate automatically creating Fakes.

[younata]

Handrolling fakes is a pain. It would be awesome to be able to write:

@AutoFake final class FakeThing: Thing {}

and have Swift just... generate the thing for us!

This probably isn't as simple as I'd like it to be, sadly.

[younata]

This seems possible using members macro, and the syntax would look like:

@FakeFor(Thing.self)
final class FakeThing {}

But I have a very poor understanding of actually working with swift-syntax to write a macro. So, this is on hold until I find more time to go through and figure all this out.