message: Add missing wrapping_add() caught by test vectors
diff: @@ -231,7 +231,7 @@ impl DiversifierIndex {
  pub fn increment(&mut self) -> Result<(), ()> {
  let mut k = 0;
  loop {
  - self.0[k] += 1;
  + self.0[k] = self.0[k].wrapping_add(1);
  if self.0[k] != 0 {
  // No overflow
  return Ok(());
  