[clang-tools-extra] [clang-tidy][NFC] Refactor `modernize-use-trailing-return-type-check` check code and tests (PR #140759)

[Carlos Galvez via cfe-commits]

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@@ -113,7 +113,7 @@ struct UnqualNameVisitor : public RecursiveASTVisitor<UnqualNameVisitor> {
 };
 } // namespace
 
-constexpr llvm::StringLiteral Message =
+constexpr llvm::StringLiteral MessageFunction =
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carlosgalvezp wrote:

Ok! I think this change would have been better to do in #135383, where it clearly shows that you need 2 different error messages. 

https://github.com/llvm/llvm-project/pull/140759