Make the message about name not referring to a user-defined type more generic

libsolidity/analysis/DeclarationTypeChecker.cpp

@@ -190,7 +190,7 @@ void DeclarationTypeChecker::endVisit(UserDefinedTypeName const& _typeName)
 		m_errorReporter.fatalTypeError(
 			5172_error,
 			_typeName.location(),
-			"Name has to refer to a struct, enum or contract."
+			"Name has to refer to a user-defined type."
 		);
 	}
 }