Docs: Now closed Vue PR 3399 mentioned in multiple places

[ajuvonen]

Additional context

The now-closed Vue core PR 3399 is mentioned in multiple places, such as the README and generated components.d.ts. Since TypeScript support no longer requires any special considerations as far as I know, maybe these references can be dropped?

Also about the README, Volar is now known as Vue Language Tools.

[ilyaliao]

Sorry, I didn't fully understand. Do you mean removing all the places that mention 3399?

[ajuvonen]

Yes - if the PR in question is no longer an issue regarding the use of this library, there's no need to mention it in the README or in the components.d.ts file generated. If the PR is for some reason still relevant, then this issue can be closed, it just means I didn't understand its significance.