[clang] [clang-cl] Fix value of __FUNCTION__ in MSVC mode. (PR #84014)

[Aaron Ballman via cfe-commits]

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@@ -679,6 +679,19 @@ static void printExplicitSpecifier(ExplicitSpecifier ES, llvm::raw_ostream &Out,
   Out << Proto;
 }
 
+static void AddPrefix(PrintingPolicy &Policy, QualType T,
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AaronBallman wrote:

This is a pretty non-descriptive function name; the caller will have no idea what kind of prefix it adds. But trying to come up with a name for this is... not easy.

`MaybePrintTagKeywordIfSupressingScopes` is not super great either. :-D

https://github.com/llvm/llvm-project/pull/84014