B03001 - trapdoors while blind and levitating

The seetrap() was done for trapdoors & holes independent of whether a
message was printed.  Move the seetrap call into fall_through where
the message logic lives (Sokoban holes always activate).

doc/fixes34.1

@@ -139,6 +139,7 @@ dropping gold on an altar printed no message and didn't change gnostic conduct
 don't allow cursed daggers thrown by monsters to go thru closed doors
 hero polymorphed into an exploding monster should explode when attacking
 	thin air, just like the monster itself
+don't mark holes/trapdoors as seen if you levitate over them while blind
 
 
 Platform- and/or Interface-Specific Fixes

src/trap.c

@@ -331,6 +331,7 @@ boolean td;	/* td == TRUE : trap door or hole */
 
 	if(td) {
 	    struct trap *t=t_at(u.ux,u.uy);
+	    seetrap(t);
 	    if (!In_sokoban(&u.uz)) {
 		if (t->ttyp == TRAPDOOR)
 			pline("A trap door opens up under you!");
@@ -823,8 +824,8 @@ glovecheck:		(void) rust_dmg(uarmg, "gauntlets", 1, TRUE, &youmonst);
 		break;
 	    case HOLE:
 	    case TRAPDOOR:
-		seetrap(trap);
 		if (!Can_fall_thru(&u.uz)) {
+		    seetrap(trap);	/* normally done in fall_through */
 		    impossible("dotrap: %ss cannot exist on this level.",
 			       defsyms[trap_to_defsym(ttype)].explanation);
 		    break;		/* don't activate it after all */