trim.8: update the manual with references to zpool-trim and fsck_ffs -E

MFC after:	3 days

usr.sbin/trim/trim.8

@@ -23,7 +23,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd July 20, 2025
+.Dd October 1, 2025
 .Dt TRIM 8
 .Os
 .Sh NAME
@@ -48,9 +48,16 @@
 The
 .Nm
 utility erases specified region of the device.
-It is mostly relevant for storage that implement trim (like flash based,
+It is mostly relevant for a storage that implements trim (like flash based,
 or thinly provisioned storage).
 .Sy All erased data is lost.
+Alternatively, refer to the
+.Xr fsck_ffs 8
+command having a flag
+.Fl E
+to trim populated UFS, and to the
+.Xr zpool-trim 8
+command to trim existing ZFS pool.
 .Pp
 The following options are available:
 .Bl -tag -width indent
@@ -156,7 +163,9 @@ is special device file not supporting DIOCGMEDIASIZE
 .Xr sysexits 3 ,
 .Xr ada 4 ,
 .Xr da 4 ,
-.Xr nda 4
+.Xr nda 4 ,
+.Xr fsck_ffs 8 ,
+.Xr zpool-trim 8
 .Sh HISTORY
 The
 .Nm