thawing ice fix

Ice in front of a raised drawbridge was desccribed as "[ice:19?]"
and didn't present any thaw status when hero was close.

src/pager.c

@@ -547,7 +547,7 @@ ice_descr(coordxy x, coordxy y, char *outbuf)
         neardist = (r * r) * 2 - r; /* same as r*r + r*(r-1) */
 
     iflags.ice_rating = -1; /* secondary output, for 'mention_decor' */
-    if (levl[x][y].typ != ICE) {
+    if (SURFACE_AT(x, y) != ICE) {
         Sprintf(outbuf, "[ice:%d?]", (int) levl[x][y].typ);
     } else if ((distu(x, y) > neardist
                 || (!cansee(x, y) && (!u_at(x, y) || Levitation)))