Fix off-by-one in collision logic

src/collision.c

@@ -9,8 +9,7 @@ typedef enum {
 } coll_state_t;
 
 uint8_t can_move_to(uint8_t x, uint8_t y) {
-    const uint8_t coll =
-        ((uint8_t*)MAP.collision_ptr)[y * (MAP.map_width + 1) + x];
+    const uint8_t coll = ((uint8_t*)MAP.collision_ptr)[y * MAP.map_width + x];
     return coll & COLLF_WALK;
 }