zfs list: add '-t fs' and '-t vol' options
Because "filesystem" and "volume" are just too long!
Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #15864