Fix spawned coins not being collectible until after the peak of their arc (#806)

If a spawned coin lands on the same frame it hits the peak of its arc, it will never have vertical speed < 0, so it will never be collectible.

Making this also set the coin to tangible if it has 0 speed fixes this issue.

src/game/behaviors/coin.inc.c

@@ -131,7 +131,7 @@ void bhv_coin_loop(void) {
         }
     }
 
-    if (o->oVelY < 0) {
+    if (o->oVelY <= 0) {
         cur_obj_become_tangible();
     }