Add TypeScript type-checking to all rules

[bmish]

We don't need to convert our JavaScript files to TypeScript, but by adding JSDoc comments with types and using the TypeScript checkJs option, we can get the benefits of type-checking. See this PR for an example and list of benefits: square/eslint-plugin-square#723.

[michaelfaith]

Would you been open to a full migration to TypeScript if someone contributed it? Or would you prefer js with doc comments?

[bmish]

I'm open to that -- a full migration to TypeScript is the end-goal. Jsdoc comments can just be a nice intermediary step to get there.

We would want to do this as a follow-up to the ESM migration which is already open:

• feat!: move to ESM only #516

[michaelfaith]

Great, i'd be down to help with that.