Seat method to set the current trust status.

In terminal-based GUI applications, this is passed through to
term_set_trust_status, to toggle whether lines are prefixed with the
new trust sigil. In console applications, the function returns false,
indicating to the backend that it should employ some other technique
for spoofing protection.

windows/winplink.c

@@ -106,6 +106,7 @@ static const SeatVtable plink_seat_vt = {
     nullseat_get_windowid,
     nullseat_get_window_pixel_size,
     console_stripctrl_new,
+    console_set_trust_status,
 };
 static Seat plink_seat[1] = {{ &plink_seat_vt }};