See #2371

This changes the rejected value to TimeotError when AbortSignal:timeout() is initially aborted.

As stated in docs:

The signal will abort with its AbortSignal.reason property set to a TimeoutError DOMException on timeout, or an AbortError DOMException if the operation was user-triggered.

Checklist

• I have read the documentation.
• I have included a pull request description of my changes.
• I have included some tests.
• If it's a new feature, I have included documentation updates in both the README and the types.