renice does not support options

[e-kwsm]

revision: f61ed28

Document and help message state that renice take options:
https://github.com/uutils/util-linux/blob/f61ed28449d5cf23cae0aff849443e9781daae82/src/uu/renice/renice.md

but currently it takes positional arguments only:

$ ./target/debug/util-linux renice 19 -p $$
error: unexpected argument '-p' found

  tip: to pass '-p' as a value, use '-- -p'

Usage: ./target/debug/util-linux renice [--priority|--relative] priority [-g|-p|-u] identifier...

For more information, try '--help'.