[clang] [clang-cl][flang][dxc] Fix opts exposed to clang-cl/dxc by mistake (PR #118640)

[Mészáros Gergely via cfe-commits]

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@@ -1989,7 +1989,7 @@ def : Flag<["-"], "fno-diagnostics-color">, Group<f_Group>,
   Visibility<[ClangOption, CLOption, DXCOption, FlangOption]>,
   Alias<fno_color_diagnostics>;
 def fdiagnostics_color_EQ : Joined<["-"], "fdiagnostics-color=">, Group<f_Group>,
-  Visibility<[ClangOption, CLOption, DXCOption, FlangOption]>,
+  Visibility<[ClangOption, FlangOption]>,
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Maetveis wrote:

I think this is also reasonable given that both `-fdiagnostic-color` and `-fno-diagnostic-color` were already exposed to `clang-cl` (prior to being exposed to flang).

https://github.com/llvm/llvm-project/pull/118640