[clang] [Clang][Diagnostics] Mention 'import std' in typeid diagnostic (PR #173236)

[Chuanqi Xu via cfe-commits]

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@@ -8428,6 +8428,8 @@ def err_bad_dynamic_cast_not_ptr : Error<"cannot use dynamic_cast to convert fro
 def err_bad_dynamic_cast_not_polymorphic : Error<"%0 is not polymorphic">;
 
 // Other C++ expressions
+def err_need_header_or_std_before_typeid : Error<
+  "you need to include <typeinfo> or import std before using the 'typeid' operator">;
 def err_need_header_before_typeid : Error<
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ChuanqiXu9 wrote:

You can use `%select` clause to avoid redundency. Search `%select` in the same file for examples.

https://github.com/llvm/llvm-project/pull/173236