Silence clippy needless_range_loop warnings

I'm using range loops explicitly to make certain logic clearer.

src/primitives/poseidon.rs

@@ -147,6 +147,7 @@ fn permute<F: FieldExt, S: Spec<F>>(
     let apply_mds = |state: &mut S::State| {
         let mut new_state = S::State::default();
         // Matrix multiplication
+        #[allow(clippy::needless_range_loop)]
         for i in 0..S::arity() {
             for j in 0..S::arity() {
                 new_state.as_mut()[i] += mds[i].as_ref()[j] * state.as_ref()[j];

src/primitives/poseidon/mds.rs

@@ -50,6 +50,7 @@ pub(super) fn generate_mds<F: FieldExt>(
         // and we want to rely on the reference impl for MDS security, so we use the same
         // formulation.
         let mut mds = vec![vec![F::zero(); arity]; arity];
+        #[allow(clippy::needless_range_loop)]
         for i in 0..arity {
             for j in 0..arity {
                 let sum = xs[i] + ys[j];
@@ -109,6 +110,7 @@ mod tests {
         let (mds, mds_inv) = generate_mds::<Fp>(&mut grain, arity, 0);
 
         // Verify that MDS * MDS^-1 = I.
+        #[allow(clippy::needless_range_loop)]
         for i in 0..arity {
             for j in 0..arity {
                 let expected = if i == j { Fp::one() } else { Fp::zero() };