storage: iterator_concept

src/entt/entity/storage.hpp

@@ -161,6 +161,7 @@ public:
     using pointer = input_iterator_pointer<value_type>;
     using reference = value_type;
     using iterator_category = std::input_iterator_tag;
+    using iterator_concept = std::forward_iterator_tag;
 
     constexpr extended_storage_iterator()
         : it{} {}