Support for `using` keyword

[fregante]

I don't see any commits related to this so I think this keyword is not supported yet. I created an issue in the eslint repo to track it, but I think it has to be fixed here, so I'm opening it for visibility.

Sample code:

{
  const getResource = () => {
    return {
      [Symbol.dispose]: () => {
        console.log('Hooray!')
      }
    }
  }
  using resource = getResource();
}

Related:

• https://github.com/eslint/eslint/issues/17701
• TypeScript 5.2 already supports it: https://www.totaltypescript.com/typescript-5-2-new-keyword-using
• The proposal is at stage 3: https://github.com/tc39/proposal-explicit-resource-management

[mdjermanovic]

As stated in What ECMAScript features do you support, we are implementing features as they are finalized. When this proposal reaches stage 4, we'll add support for this syntax.