Update pybind11.h

Author: henryiii

include/pybind11/pybind11.h

@@ -1976,15 +1976,15 @@ struct iterator_access {
     }
 };
 
-template <typename Iterator, typename ResultType = decltype(((*std::declval<Iterator>()).first)) >
+template <typename Iterator, typename ResultType = decltype((*std::declval<Iterator>()).first) >
 struct iterator_key_access {
     using result_type = ResultType;
     result_type operator()(Iterator &it) const {
         return (*it).first;
     }
 };
 
-template <typename Iterator, typename ResultType = decltype(((*std::declval<Iterator>()).second))>
+template <typename Iterator, typename ResultType = decltype((*std::declval<Iterator>()).second)>
 struct iterator_value_access {
     using result_type = ResultType;
     result_type operator()(Iterator &it) const {