Incorrect rational division

[Shoeboxam]

The denominator is incorrect in the rational division routines:

https://github.com/cmpute/dashu/blob/da5723435b13552bec2e95053e9beea82a8fe571/rational/src/div.rs#L100C1-L116C2

I believe it should be:

RBig(Repr {
    numerator: a / &g,
    denominator: b * (i / g),
})

[Shoeboxam]

Here's a failing test case that demonstrates it:

assert_eq!(rbig!(-2 / 3) / ubig!(4), rbig!(-1 / 6));

[cmpute]

Here's a failing test case that demonstrates it:

assert_eq!(rbig!(-2 / 3) / ubig!(4), rbig!(-1 / 6));

thanks for reporting, I will try to fix this in the following two weeks