Make `asyncio.Lock.locked()` return `True` when there are waiters

Bug report

Bug description:

In issue https://github.com/python/cpython/issues/97028 everyone seemed to agree that asyncio.{Lock,Semaphore}.locked() should return True if there are waiters, but this change was implemented only for Semaphore.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-153989

先閱讀 asyncio.Lock.locked() 以及 asyncio.Semaphore.locked()，然後查看 issue 97028 以了解已達成共識的語意。開始之前檢查已連結的 PR gh-153989，因為其中可能已經包含這項工作；完成條件是：當 lock 有等待者時，Lock.locked() 回傳 True，並提供相應的測試以及針對現有 lock 狀態的行為。