zfs-list.8: Typo in example number

[Defenso-QTH]

Currently:

.Ss Example 1 : No Listing ZFS Datasets

But this is a cross reference from zfs.8:

.\" These are, respectively, examples 5 from zfs.8
.\" Make sure to update them bidirectionally

Expected:

.Ss Example 5 : No Listing ZFS Datasets