Ignore allocator hardcoded to match std::map

include/nlohmann/json.hpp

@@ -496,6 +496,7 @@ class basic_json
     using object_t = ObjectType<StringType,
           basic_json,
           object_comparator_t,
+          // TODO: AllocatorType<ObjectType::value_type>
           AllocatorType<std::pair<const StringType,
           basic_json>>>;