fn build_two_to_the_nth<M: IsModulus<UnsignedInteger<N>> + Clone, const N: usize>(
) -> FieldElement<MontgomeryBackendPrimeField<M, N>> {
    // The hex used to build the FieldElement is a 1 followed by N * 16 zeros
    let mut two_to_the_nth = String::with_capacity(N * 16);
    for _ in 0..two_to_the_nth.capacity() - 1 {
        two_to_the_nth.push('1');
    }
    FieldElement::from_hex_unchecked(&two_to_the_nth) + FieldElement::one()
}
Builds a `FieldElement` for `2^(N*16)`, where `N` is the number of limbs of the `UnsignedInteger`
used for the prime field.
crates/crypto/src/hash/hash_to_field.rs