[clang] [C23] Fix typeof handling in enum declarations (PR #146394)

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https://github.com/Sirraide commented:

One more thing I thought of: What about C++ edge cases, e.g. both Clang and GCC accept this... which doesn’t quite seem right to me (https://godbolt.org/z/K58eEvG9P):
```c++
typeof(int){} x; // Probably parsed as typeof(int{})
```

https://github.com/llvm/llvm-project/pull/146394