Properly format NAME subsection of zfs/zpool subcommands

Use proper names (i.e. zfs-allow and zpool-add) in NAME subsections
of zfs/zpool subcommands instead of current "pretty-printed" ones as
makewhatis utilities (or some implementations of it, namely the one
from mandoc suite used in FreeBSD) look not only at the document title
but also in NAME subsection, adding zfs(8)/zpool(8) to search results
which is not correct. (Common sense and other utilities splitting
subcommands in multiple man pages, e.g. git, do the same.)

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: xtouqh <xtouqh@hotmail.com>
Closes #11086

man/man8/zfs-mount.8

@@ -34,29 +34,29 @@
 .Dt ZFS-MOUNT 8
 .Os
 .Sh NAME
-.Nm zfs Ns Pf - Cm mount
+.Nm zfs-mount
 .Nd Manage mount state of ZFS file systems.
 .Sh SYNOPSIS
-.Nm
+.Nm zfs
 .Cm mount
-.Nm
+.Nm zfs
 .Cm mount
 .Op Fl Oflv
 .Op Fl o Ar options
 .Fl a | Ar filesystem
-.Nm
+.Nm zfs
 .Cm unmount
 .Op Fl fu
 .Fl a | Ar filesystem Ns | Ns Ar mountpoint
 .Sh DESCRIPTION
 .Bl -tag -width ""
 .It Xo
-.Nm
+.Nm zfs
 .Cm mount
 .Xc
 Displays all ZFS file systems currently mounted.
 .It Xo
-.Nm
+.Nm zfs
 .Cm mount
 .Op Fl Oflv
 .Op Fl o Ar options
@@ -105,7 +105,7 @@ Report mount progress.
 Attempt to force mounting of all filesystems, even those that couldn't normally be mounted (e.g. redacted datasets).
 .El
 .It Xo
-.Nm
+.Nm zfs
 .Cm unmount
 .Op Fl fu
 .Fl a | Ar filesystem Ns | Ns Ar mountpoint