Allow Unicode string imports and exports

[DanielRosenwasser]

tc39/ecma262#2154

import { "😊" as yay } from "...";

yay();

export { yay as "🦈" };

The above code should be supported.

The minimum viable product should have tests for:

• esnext module output
• es2015 or similar module output just to get an error
• --declaration emit
  • Specific declaration emit where the compiler might generate import() type syntax.
• Quick info, and error message tests where we might generate import() type syntax
• Completions in import {} and export {} lists
• Go-to-definition

It is likely that we would never try to emit our own import() type syntax.

[Kingwl]

I’m happy to work on this (If @weswigham does not started)

[weswigham]

I have not, and probably wouldn't until after the RC cut. If you do work on it, just keep in mind that something like #40708 we intend as a followup for this change, rather than a part of it. For this, we just wanna get the new syntax down, without expanding any TS syntax yet.

[ExE-Boss]

Duplicate of #40594