Pass Mailbox instead of Game on related functions for clarity

src/search/quiescence.rs

@@ -30,7 +30,7 @@ pub fn quiescence(game: &mut Game, mut alpha: i32, beta: i32) -> (Option<Move>,
         })
         .collect();
 
-    captures.sort_unstable_by_key(|mv| score_by_mvv_lva(&game, *mv));
+    captures.sort_unstable_by_key(|mv| score_by_mvv_lva(&game.mailbox, *mv));
 
     for mv in captures {
         game.make_move(&mv);