docs: clarify trace function implementation used by default depending on Python version (#2067) * docs: clarify trace function implementation used by default depending on the Python version * Apply suggestions from code review Co-authored-by: devdanzin <74280297+devdanzin@users.noreply.github.com> * Apply suggestions from code review --------- Co-authored-by: Ned Batchelder <ned@nedbatchelder.com> Co-authored-by: devdanzin <74280297+devdanzin@users.noreply.github.com>