Div(BigDecimal, BigDecimal) should yield BigRational

[rubdos]

Dividing two BigDecimal's should yield a BigRational, per feature. Additionally, division by another integer numeral could be implemented to yield a BigRational.

[kestred]

I could see this being a desirable behavior for scientific use (although not what I in particular would expect or want), but if this was implemented, it'd be important for it to be ergonomic to turn a BigRational back into a BigDecimal.