[clang] [llvm] [coroutine] Implement llvm.coro.await.suspend intrinsic (PR #79712)

[Chuanqi Xu via cfe-commits]

================
@@ -1744,6 +1744,273 @@ a call to ``llvm.coro.suspend.retcon`` after resuming abnormally.
 In a yield-once coroutine, it is undefined behavior if the coroutine
 executes a call to ``llvm.coro.suspend.retcon`` after resuming in any way.
 
+.. _coro.await.suspend:
+
+'llvm.coro.await.suspend' Intrinsic
----------------
ChuanqiXu9 wrote:

```suggestion
'llvm.coro.await.suspend_void' Intrinsic
```

I'd like to rename it to keep consistency. nit

https://github.com/llvm/llvm-project/pull/79712