Add more explicit helpless reasons

Instead of just "while helpless", the death reason will tell
more explicitly why the player was helpless.  For example:
"while frozen by a monster's gaze"

src/steal.c

@@ -361,6 +361,7 @@ gotobj:
 			named++;
 			/* the following is to set multi for later on */
 			nomul(-armordelay);
+			multi_reason = "taking off clothes";
 			nomovemsg = 0;
 			remove_worn_item(otmp, TRUE);
 			otmp->cursed = curssv;