Global JSX to local JSX w/ generics

[wooorm]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)
• If applicable, I’ve added docs and tests

Description of changes

Cleaner but completely broken version of what GH-6 attempts.
This does not remove functionality (components).
But because TS limitations (and likely that jsx types are not very good), we can’t infer some IntrinsicElements registry from a jsx function or an Element type.

[wooorm]

Closing this, I think it’s better for folks to define JSX: ae638ba. Similarly to how we expect a runtime to be passed in, it makes sentence that types are passed in too. And while TS doesn’t have a way to pass namespaces, a global seems good. Especially a global that is in use by millions of code examples out there.