fix: provide useful behavior of default `py::slice` (#5620)

* Change behavior of default py::slice

* make clang-tidy happy

* Update tests/test_pytypes.py

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Co-authored-by: Bryn Lloyd <12702862+dyollb@users.noreply.github.com>
Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>
3 files changed