Improve error message for duplicate parameters

src/expression-classifier.h

Index: src/expression-classifier.h
diff --git a/src/expression-classifier.h b/src/expression-classifier.h
index 6edb99e8388427514f662f312c6341935150edac..fc89015d1fcee8a8f88cbb20169476cb523b14b1 100644
--- a/src/expression-classifier.h
+++ b/src/expression-classifier.h
@@ -157,8 +157,7 @@ class ExpressionClassifier {
     if (!is_valid_formal_parameter_list_without_duplicates()) return;
     invalid_productions_ |= DistinctFormalParametersProduction;
     duplicate_formal_parameter_error_.location = loc;
-    duplicate_formal_parameter_error_.message =
-        MessageTemplate::kStrictParamDupe;
+    duplicate_formal_parameter_error_.message = MessageTemplate::kParamDupe;
     duplicate_formal_parameter_error_.arg = nullptr;
   }