feat: vectorize functions with void return type (#1969)

* Allow function/functor passed to py::vectorize to return void

* Stealing @sizmailov's test and fixing unused argument warning

* Add missing std::move()

RVO doesn't work here because function return type is different from
actual returned type

* remove extra EOL

* docs: add a few details

* chore: pre-commit autoupdate

* Remove array_iterator, array_begin, and array_end (in detail namespace)

Co-authored-by: Sergei Izmailov <sergei.a.izmailov@gmail.com>
Co-authored-by: Henry Schreiner <henryschreineriii@gmail.com>