[clang] Remove duplicate API (PR #132776)

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Jugst3r wrote:

Sure, I did what @Endilll suggested. It is kind of unfortunate to have such similar type names :/. I don't think I can use the [[attribute]] C++-style syntax, maybe there is another syntax I am not aware of, but for the mean time I put the deprecated inside the comments.

https://github.com/llvm/llvm-project/pull/132776