message: Add comment why zero is the correct return value
diff: @@ -60,6 +60,9 @@ impl Decimal {
  if let Ok(factor) = Uint128::new(10).checked_pow(digits) {
  Self(atomics.checked_div(factor)?)
  } else {
  + // In this case `factor` exceeds the Uint128 range.
  + // Any Uint128 `x` divided by `factor` with `factor > Uint128::MAX` is 0.
  + // Try e.g. Python3: `(2**128-1) // 2**128`
  Self(Uint128::zero())
  }
  }
  