Replace `with_argparser_and_unknown_args` in docs

Fixed error in set --long, which should be set -v

(Cmd) set --long
Usage: set [-h] [-v] [param] [value]
Error: unrecognized arguments: --long

Fix typo

Remove unnecessary runtime dependency on setuptools

The package does not seem to use setuptools or pkg_resources anywhere,
and the dependency is probably leftover after migration to
importlib.metadata.