Index type props display as strings, which should be aligned to the
left not to the right.
Before:
```
FreeBSD-13_0-CURRENT-r356528 ➜ ~ zfs list -ro name,aclmode,mountpoint
NAME ACLMODE MOUNTPOINT
p0 passthrough /p0
p0/foo discard /p0/foo
```
After:
```
FreeBSD-13_0-CURRENT-r356528 ➜ ~ zfs list -ro name,aclmode,mountpoint
NAME ACLMODE MOUNTPOINT
p0 passthrough /p0
p0/foo discard /p0/foo
```
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#9912
fe7c15985b