The private aliases primitive_iterator_t, internal_iterator and
output_adapter_t are not used anywhere: iter_impl, binary_writer and
the tests refer to the detail:: names directly. As the aliases are
private, no user or derived class can depend on them. The
internal_iterator.hpp include stays because iter_impl needs it.
Part of #5724
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann
1d98396a19