redo method

void redo()

Redo the last undone move and restore the forth state.

Implementation

void redo() {
  if (redoHistory.isNotEmpty) {
    String currentFEN = toFEN();
    if (redoHistory.last == currentFEN) {
      redoHistory.removeLast();
      return;
    }
    history.add(currentFEN);
    initFEN(redoHistory.removeLast());
  }
}