Fix autodescribe after reading a cursed scroll of gold detection

Autodescribe was not updating during browse_map() when the cursor was
moved over a gold glyph that was actually a trap, causing the trap to
be described as the previous square that the cursor was on (probably
"unexplored area") instead of as gold pieces.  This was especially
noticeable when using OPTIONS=whatis_coord:m, because the coordinate
was not updating when moving the cursor over the trap.

src/detect.c

@@ -924,7 +924,7 @@ static void
 display_trap_map(struct trap *ttmp, int cursed_src)
 {
     struct monst *mon;
-    int door, glyph, ter_typ = TER_DETECT | TER_TRP;
+    int door, glyph, ter_typ = TER_DETECT | ( cursed_src ? TER_OBJ : TER_TRP );
     coord cc;
 
     cls();