contrib/debian: add new manpages to installation list

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Shengqi Chen <harry-chen@outlook.com>
Closes #16609

contrib/debian/openzfs-zfsutils.install

@@ -98,6 +98,7 @@ usr/share/man/man8/zpool-attach.8
 usr/share/man/man8/zpool-checkpoint.8
 usr/share/man/man8/zpool-clear.8
 usr/share/man/man8/zpool-create.8
+usr/share/man/man8/zpool-ddtprune.8
 usr/share/man/man8/zpool-destroy.8
 usr/share/man/man8/zpool-detach.8
 usr/share/man/man8/zpool-ddtprune.8
@@ -113,6 +114,7 @@ usr/share/man/man8/zpool-list.8
 usr/share/man/man8/zpool-offline.8
 usr/share/man/man8/zpool-online.8
 usr/share/man/man8/zpool-prefetch.8
+usr/share/man/man8/zpool-prefetch.8
 usr/share/man/man8/zpool-reguid.8
 usr/share/man/man8/zpool-remove.8
 usr/share/man/man8/zpool-reopen.8