Apply unified code quality standards

[remcohaszing]

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

• Code is formatted using Prettier, except markdown files.
• JavaScript code is linted using XO.
• Markdown is checked using remark-preset-wooorm.
• GitHub actions is used to validate tests and code quality.
• No package-lock.json file is generated.
• Dependency version ranges of the form ^x.0.0 are used.

Many configurations have been copy-pasted from unified.

This is an initial step to start enhancing unified-language-server.

• A broken test has been skipped.
• Due to the synchronous nature, CJS is still used.
• TypeScript checks aren’t implemented yet.
• Code coverage hasn’t been implemented yet.

[ChristianMurphy]

Thanks @remcohaszing!

[wooorm]

Looks good. I didn’t check every line as it’s a lot and I assume it’s good. Do share if there’s anthing in particular that you want to be reviewed.

[remcohaszing]

I think the most important thing to review is that it still works.

I verified this manually by using it with vim-lsp before and after these changes.

[wooorm]

I haven’t used this before, so I can’t help there, but 👍 on how you checked it

[wooorm]

Good to go I think?

[remcohaszing]

Yep, this is ready to go.

[wooorm]

Landed!