refactor: Improve typescript types and strictness

[scagood]

This adds a much stricter tsconfig.

It looks like this does now correctly export the types too.

[scagood]

I do still need to work on the type tests, I may see if I can steal from #366 😅

[aladdin-add]

LGTM. confirmed the generated typings is right. 👍

[aladdin-add]

technically it fixes #320.

Did you not close it for the subsequent task of adding type tests? 😄

[aladdin-add]

@voxpelli, @MichaelDeBoey, PTAL. :)

[MichaelDeBoey]

This makes me think that we should port the codebase to pure TS at one point in the (near) future 🤔

CC/ @eslint-community/eslint-plugin-node

[scagood]

This makes me think that we should port the codebase to pure TS at one point in the (near) future 🤔

I am currently in the jsdoc > typescript camp for a few reasons:

1. Any transform causes more problems in the future than they solve now
2. I prefer adding documentation lines to functions, meaning I have to make a jsdoc block anyway
3. The allowJs flag means that we can use all of typescript's typing benefits without the transpilation step.

Its not that I am not against using typescript, I just find that I prefer jsdoc 🤔