* chore: add clang-format

* Removing check-style (Classic check-style)

Ported from @henryiii's https://github.com/pybind/pybind11/pull/3683/commits/53056b1b0eeb4136b0d7362a8261b6b59658e0a7

* Automatic clang-format changes (NO manual changes).

Co-authored-by: Henry Schreiner <henryschreineriii@gmail.com>