fix: add new using declarations to Cmd concept

Author: ggabriel96

include/opzioni/concepts.hpp

@@ -17,9 +17,12 @@ concept Container = std::ranges::range<T> && std::is_default_constructible_v<T>
 template <typename T>
 concept Cmd = requires(T) {
   typename T::arg_names;
+  typename T::arg_abbrevs;
+  typename T::arg_kinds;
   typename T::arg_types;
   typename T::arg_tags;
   typename T::subcmd_types;
+  typename T::amount_pos;
 };
 
 } // namespace opz::concepts