ls: user & group column alignment in long output format

[cbjadwani]

When files/devices in a directory belong to different users/groups the output can be misaligned.

$ ./target/release/ls -l /dev/input | head -5
drwxr-xr-x 2 root root 180 Apr 26 14:28 by-id
drwxr-xr-x 2 root root 260 Apr 26 14:28 by-path
-rw-rw---- 1 root input   0 Apr 26 14:27 event0
-rw-rw---- 1 root input   0 Apr 26 14:27 event1
-rw-rw---- 1 root input   0 Apr 26 14:27 event10

$ /usr/bin/ls -l /dev/input | head -5
total 0
drwxr-xr-x 2 root root     180 Apr 26 14:28 by-id
drwxr-xr-x 2 root root     260 Apr 26 14:28 by-path
crw-rw---- 1 root input 13, 64 Apr 26 14:27 event0
crw-rw---- 1 root input 13, 65 Apr 26 14:27 event1