[Add] Attributes names for Concat Operator

include/aidge/operator/Concat.hpp

@@ -26,7 +26,7 @@
 #include "aidge/utils/Types.h"
 
 namespace Aidge {
-enum class ConcatAttr { NbInputs, Axis};
+enum class ConcatAttr { NbInputs, Axis };
 
 class Concat_Op : public Operator,
     public Registrable<Concat_Op, std::string, std::unique_ptr<OperatorImpl>(const Concat_Op&)>,
@@ -183,4 +183,12 @@ inline std::shared_ptr<Node> Concat(const IOIndex_t nbIn, const DimIdx_t axis =
 }
 }
 
+namespace {
+    template <>
+    const char* const EnumStrings<Aidge::ConcatAttr>::data[] = {
+        "NbInputs",
+        "Axis"
+    };
+}
+
 #endif /* AIDGE_CORE_OPERATOR_CONCAT_H_ */