custom choice dialogs Stay/Leave can't both use Enter Key.

And since depending on context they could both mean 'Cancel' but 'Leave' could be a positive action in some contexts, I've just given them no keys.

src/game/boe.specials.cpp

@@ -2567,9 +2567,11 @@ void oneshot_spec(const runtime_state& ctx) {
 				break;
 			get_strs(strs, ctx.cur_spec_type, spec.m1);
 			if(spec.m3 > 0) {
+				// The first button defaults to OK if toggle is on
 				buttons[0] = 1;
 				buttons[1] = spec.ex1a;
 				buttons[2] = spec.ex2a;
+				// If button 2 and/or button 3 are provided, the first button becomes a Leave button!
 				if((spec.ex1a >= 0) || (spec.ex2a >= 0))
 					buttons[0] = 9;
 			}