Add JSDoc based types

[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

Add JSDoc based types

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Notes

• The check functions should allow unknown values; but typescript becomes really annoying when ducktyping whether something in fact looks like a certain node. Any ideas?
• I’m messing up somewhere, I don’t know how to solve the “Assertions require every name in the call target to be declared with an explicit type annotation.” error.