Function factor_quartic_inner

pub fn factor_quartic_inner(
    a: f64,
    b: f64,
    c: f64,
    d: f64,
    rescale: bool,
) -> Option<ArrayVec<(f64, f64), 2>>

Factor a quartic into two quadratics.

Attempt to factor a quartic equation into two quadratic equations. Returns None either if there is overflow (in which case rescaling might succeed) or the factorization would result in complex coefficients.

Discussion question: distinguish the two cases in return value?