algorithms/mul_redc: Ideally this turns into a cmov, which makes the whole mul_redc constant

[github-actions]

On 2024-12-16 @prestwich wrote in e657576 “Merge pull request #402 from recmo/recmo/montgomery”:

Ideally this turns into a cmov, which makes the whole mul_redc constant
time.

#[inline]
#[must_use]
#[allow(clippy::needless_bitwise_bool)]
fn reduce1_carry<const N: usize>(value: [u64; N], modulus: [u64; N], carry: bool) -> [u64; N] {
    let (reduced, borrow) = sub(value, modulus);
    // TODO: Ideally this turns into a cmov, which makes the whole mul_redc constant
    // time.
    if carry | !borrow {
        reduced
    } else {
        value
    }

From src/algorithms/mul_redc.rs:130