Trailing zero inconsistently added to result

[janekfleper]

Depending on the precision of the resulting decimal there is sometimes a trailing zero added. This happens every 9 decimal digits. 👀
A minimal example to reproduce the issue is:

let ten = Decimal::new(10, 0);

println!("\nDecimal numbers from 1 to 1e-28:");
for n in 0..=28 {
    println!("n = {:2}, 10^-n = {}", n, ten.powi(-n as i64));
}

The output of the example code is:

Decimal numbers from 1 to 1e-28:
n =  0, 10^-n = 1
n =  1, 10^-n = 0.10
n =  2, 10^-n = 0.01
n =  3, 10^-n = 0.001
n =  4, 10^-n = 0.0001
n =  5, 10^-n = 0.00001
n =  6, 10^-n = 0.000001
n =  7, 10^-n = 0.0000001
n =  8, 10^-n = 0.00000001
n =  9, 10^-n = 0.000000001
n = 10, 10^-n = 0.00000000010
n = 11, 10^-n = 0.00000000001
n = 12, 10^-n = 0.000000000001
n = 13, 10^-n = 0.0000000000001
n = 14, 10^-n = 0.00000000000001
n = 15, 10^-n = 0.000000000000001
n = 16, 10^-n = 0.0000000000000001
n = 17, 10^-n = 0.00000000000000001
n = 18, 10^-n = 0.000000000000000001
n = 19, 10^-n = 0.00000000000000000010
n = 20, 10^-n = 0.00000000000000000001
n = 21, 10^-n = 0.000000000000000000001
n = 22, 10^-n = 0.0000000000000000000001
n = 23, 10^-n = 0.00000000000000000000001
n = 24, 10^-n = 0.000000000000000000000001
n = 25, 10^-n = 0.0000000000000000000000001
n = 26, 10^-n = 0.00000000000000000000000001
n = 27, 10^-n = 0.000000000000000000000000001
n = 28, 10^-n = 0.0000000000000000000000000001

I initially encountered this issue when using the decimal type in Typst, see typst/typst#6065 for a few more examples.
The Typst compiler uses the latest version 1.36.0, see cargo.toml.