cleanup and fix warnings

src/repr/coords.rs

@@ -20,6 +20,7 @@ impl CoordPair {
         Self(row * Board::BOARD_SIZE + col)
     }
 
+    #[allow(clippy::wrong_self_convention)]
     fn into_indexes(&self) -> (CoordAxis, CoordAxis) {
         self.0.div_mod_floor(&Board::BOARD_SIZE)
     }