Pass Mailbox instead of Game on related functions for clarity

src/search/negamax.rs

@@ -23,7 +23,7 @@ pub fn negamax(
     let mut legal_moves = 0;
 
     let mut pseudo_legal_moves = game.board.pseudo_moves_all();
-    pseudo_legal_moves.sort_unstable_by_key(|mv| score_by_mvv_lva(&game, *mv));
+    pseudo_legal_moves.sort_unstable_by_key(|mv| score_by_mvv_lva(&game.mailbox, *mv));
 
     for mv in pseudo_legal_moves {
         game.make_move(&mv);