[clang] [clang] Enable Wenum-constexpr-conversion also in system headers and … (PR #67528)

[Mariya Podchishchaeva via cfe-commits]

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@@ -405,7 +405,8 @@ def warn_fixedpoint_constant_overflow : Warning<
   InGroup<DiagGroup<"fixed-point-overflow">>;
 def warn_constexpr_unscoped_enum_out_of_range : Warning<
   "integer value %0 is outside the valid range of values [%1, %2] for the "
-  "enumeration type %3">, DefaultError, InGroup<DiagGroup<"enum-constexpr-conversion">>;
+  "enumeration type %3">, DefaultError, ShowInSystemHeader, ShowInSystemMacro,
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Fznamznon wrote:

Do we need a test for this change?

https://github.com/llvm/llvm-project/pull/67528