[llvm] [Support] Introduce formatv variant of createStringError (PR #80493)

[Alex Langford via llvm-commits]

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@@ -1261,6 +1262,15 @@ inline Error createStringError(std::errc EC, char const *Fmt,
   return createStringError(std::make_error_code(EC), Fmt, Vals...);
 }
 
+template <typename... Ts>
+inline Error createStringErrorv(std::error_code EC, const char *Fmt,
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bulbazord wrote:

I'd be fine with capitalizing the `v` at the end. I'm also alright with `createStringErrorVariadic` as well. If anyone feels particularly strongly about either of these, let me know. Otherwise I will likely choose the former.

https://github.com/llvm/llvm-project/pull/80493