Wit-bindgen support for resource subtypes

[kulakowski-wasm]

• [ ] https://github.com/WebAssembly/component-model/issues/60

Eventually, this should be defined by the component model, and the syntax by the definition of wit.

[esoterra]

I've made an issue in component model for this. I'd like to see it rendered there before we start implementing it. https://github.com/WebAssembly/component-model/issues/60

[kulakowski-wasm]

Yes, thanks for filing that!

[alexcrichton]

I'm going to close this since resources have been removed at this time and work instead needs to happen upstream in the component-model repository first.