[clang-tools-extra] [clang-tidy] Fix readability-identifier-naming FP with DefaultCase on function templates (PR #189788)

[Baranov Victor via cfe-commits]

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@@ -1303,6 +1303,10 @@ StyleKind IdentifierNamingCheck::findStyleKind(
       return SK_Function;
   }
 
+  if (isa<FunctionTemplateDecl, ClassTemplateDecl, VarTemplateDecl,
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vbvictor wrote:

Can we add comment here why we are skipping these as "invalid"

https://github.com/llvm/llvm-project/pull/189788