Change zed.service to zfs-zed.service in man page

zed.service does not exist
replaced with correct service name in man.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Closes #9581

man/man8/zfs-mount-generator.8.in

@@ -58,9 +58,9 @@ Then, enable the tracking ZEDLET:
 .RS 4
 ln -s "@zfsexecdir@/zed.d/history_event-zfs-list-cacher.sh" "@sysconfdir@/zfs/zed.d"
 
-systemctl enable zed.service
+systemctl enable zfs-zed.service
 
-systemctl restart zed.service
+systemctl restart zfs-zed.service
 .RE
 .PP
 Force the running of the ZEDLET by setting canmount=on for at least one dataset in the pool: