Correct a typo in zfs-receive.8

Should be  `-o keyformat=passphrase` instead of `-o -keyformat=passphrase`
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chuang Zhu <chuang@melty.land>
Closes #13072 

man/man8/zfs-receive.8

@@ -319,7 +319,7 @@ received as an encryption root, specify encryption properties in the same
 manner as is required for
 .Nm zfs Cm create .
 For instance:
-.Dl # Nm zfs Cm send Pa tank/test@snap1 | Nm zfs Cm recv Fl o Sy encryption Ns = Ns Sy on Fl o keyformat=passphrase Fl o Sy keylocation Ns = Ns Pa file:///path/to/keyfile
+.Dl # Nm zfs Cm send Pa tank/test@snap1 | Nm zfs Cm recv Fl o Sy encryption Ns = Ns Sy on Fl o Sy keyformat=passphrase Fl o Sy keylocation Ns = Ns Pa file:///path/to/keyfile
 .Pp
 Note that
 .Fl o Sy keylocation Ns = Ns Sy prompt