Standardize xtensor_type_caster_base signature

[AntoinePrv]

Hello,
I wonder if there is a reason why the xtensor_type_caster_base uses xt::xtensor for the signature

xtensor-python/include/xtensor-python/xtensor_type_caster_base.hpp

Line 161 in 719b9d1

static constexpr auto name = _("xt::xtensor");

instead of using numpy.ndarray[...]

xtensor-python/include/xtensor-python/pyarray.hpp

Line 72 in 719b9d1

PYBIND11_TYPE_CASTER(type, _("numpy.ndarray[") + npy_format_descriptor<T>::name + _("]"));

In my opinion, using the Numpy name is more descriptive to a Python user, and actually matches the type.

I made a quick test using

_("numpy.ndarray[") + npy_format_descriptor<typename Type::value_type>::name + _("]");

which seems to work.

I could send a PR if you are interested.

Thank you

[JohanMabille]

Good question! Honestly, I don't remember the why of this decision. @SylvainCorlay @wolfv any idea?