Development update

[zth]

I figured I'd take the time to do an update of the development process right now:

1. There's now a milestone for the next release https://github.com/rescript-association/rescript-core/milestone/1. That's the main focus for now, to finish up and get that out.
2. After that, we'll continue to focus on the DX aspects of Core. That means docstrings for anything that doesn't already have docstrings, doc generation, and looking at if there's anything we can do to improve the editor integration for Core specifically.

If you're interested in helping out, please add docstrings. Docstrings is the foundation for the documentation generation as well.