RFC: Specify that doc comments are allowed on simple union types

Hello,

I can't find any documentation on adding tsdocs to a typescript string literal type. I was wondering if the following is possible:

type InputType = 
/** the TSDoc doesn't work for num1, but I'd like it to */
| 'num1'
/** the TSDoc doesn't work for num2, but I'd also like it to */
| 'num2'

export const test = (...input: InputType[]) => {
    return input
}

// I'd like to get the TSDoc from 'num1' string literal to show up
// when inputting it into the `tac` function but it does not currently show
test('num1')

I'm not 100% tied to using string literal types, so if there is another way to do this with enums, etc., I'd love to learn 😄

If the above is not currently possible, I'd love to work to add it to tsdoc (with some guidance 😄).

Thanks!

Start with the TypeScript example in this issue and compare it with the existing TSDoc specification and parser behavior. Establish whether comments on simple union members are supported, then document the resolved syntax and expected editor output; seek maintainer guidance before implementation.