rewrite progress 2

src/board.rs

@@ -118,6 +118,12 @@ impl fmt::Display for Board {
     }
 }
 
+impl fmt::Debug for Board {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self)
+    }
+}
+
 impl Board {
     /// Create a new empty board
     pub const fn new() -> Self {