[clang] [clang][diagnostics] Add `-fdiagnostics-add-output` switch for SARIF (PR #185201)

[Aaron Ballman via cfe-commits]

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@@ -586,6 +586,20 @@ def err_analyzer_not_built_with_z3 : Error<
   "analyzer constraint manager 'z3' is only available if LLVM was built with "
   "-DLLVM_ENABLE_Z3_SOLVER=ON">;
 
+def err_diagnostic_output_no_value
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AaronBallman wrote:

This diagnostic doesn't have test coverage.

https://github.com/llvm/llvm-project/pull/185201