message: Fix clippy::match_bool
diff: @@ -2636,10 +2636,7 @@ impl BigInt {
  self.set_zero();
  } else {
  self.data.assign_from_slice(slice);
  - self.sign = match self.data.is_zero() {
  - true => NoSign,
  - false => sign,
  - }
  + self.sign = if self.data.is_zero() { NoSign } else { sign };
  }
  }
  