message: Fix typo in custom.h
diff: @@ -96,7 +96,7 @@ NAMESPACE_BEGIN(detail)
  // Zero out indices of variables that are attached to the AD graph
  template <typename T>
  void clear_diff_vars(T &value) {
  - if constexpr (is_diffarray_v<T>) {
  + if constexpr (is_diff_array_v<T>) {
  if constexpr (array_depth_v<T> > 1) {
  for (size_t i = 0; i < value.size(); ++i)
  clear_diff_vars(value.entry(i));
  