[clang] [clang][PAC] ptrauth_qualifier and ptrauth_intrinsic should only be available on Darwin (PR #153912)

[Aaron Ballman via cfe-commits]

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@@ -144,6 +144,11 @@ New Compiler Flags
 Deprecated Compiler Flags
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+- Use of ``__has_feature`` to detect the ``ptrauth_qualifier`` and ``ptrauth_intrinsics``
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AaronBallman wrote:

This isn't really a deprecated compiler flag. Perhaps we should move this to the non-comprehensive changes section? Or make up a new section for deprecated functionality?

https://github.com/llvm/llvm-project/pull/153912