Simple display and rustfmt

src/main.rs

 struct TicTacToe {
-    board: [char; 9]
+    board: [char; 9],
 }
 
 fn display(board: TicTacToe) {
-
-    println!(" {} | {} | {}",
-             board.board[0], 
-             board.board[1], 
-             board.board[2]);
-    println!("---+---+--");
-    println!(" {} | {} | {}",
-             board.board[3], 
-             board.board[4], 
-             board.board[5]);
-    println!("---+---+---");
-    println!(" {} | {} | {}",
-             board.board[6], 
-             board.board[7], 
-             board.board[8]);
+    for row in 0..3 {
+        println!(
+            " {} | {} | {}",
+            board.board[row * 3],
+            board.board[row * 3 + 1],
+            board.board[row * 3 + 2]
+        );
+    }
 }
 
 fn main() {
-    let board = TicTacToe {
-        board: ['.'; 9]
-    };
+    let board = TicTacToe { board: ['.'; 9] };
 
     display(board);
 }