pub fn two_square_minus_one(a: &u32) -> u32 {
        if *a == 0 {
            MERSENNE_31_PRIME_FIELD_ORDER - 1
        } else {
            Self::from_u64(((u64::from(*a) * u64::from(*a)) << 1) - 1)
        }
    }
TODO: See if we can optimize this function.
Computes 2a^2 - 1
crates/math/src/field/fields/mersenne31/field.rs