[clang] [llvm] [Clang] Show inlining hints for __attribute__((warning/error)) (PR #174892)

[Nick Desaulniers via cfe-commits]

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@@ -348,6 +348,12 @@ New Compiler Flags
 - New options for enabling allocation token instrumentation: ``-fsanitize=alloc-token``, ``-falloc-token-max=``, ``-fsanitize-alloc-token-fast-abi``, ``-fsanitize-alloc-token-extended``.
 - The ``-resource-dir`` option is now displayed in the list of options shown by ``--help``.
 - New option ``-fmatrix-memory-layout`` added to control the memory layout of Clang matrix types. (e.g. ``-fmatrix-memory-layout=column-major`` or ``-fmatrix-memory-layout=row-major``).
+- New option ``-fdiagnostics-show-inlining-chain=`` added to show inlining chain
+  notes for ``__attribute__((warning))`` and ``__attribute__((error))``
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nickdesaulniers wrote:

Man, C23 standardized the C++20 syntax for attributes, which uses `[[]]`. Let's use the standard syntax, throughout this PR? `[[gnu::warning]]`

https://github.com/llvm/llvm-project/pull/174892