Use {integer}::div_ceil where appropriate (Qiskit#13716)

The method was added in Rust 1.73, which was previously above our MSRV.
Recent clippy versions now warn against the workaround on complexity
grounds, since our MSRV indicates we can use the built-in version.

Author: jakelishman

crates/accelerate/src/sparse_pauli_op.rs

@@ -1161,7 +1161,7 @@ macro_rules! impl_to_matrix_sparse {
             // to keep threads busy by subdivision with minimizing overhead; we're setting the
             // chunk size such that the iterator will have as many elements as there are threads.
             let num_threads = rayon::current_num_threads();
-            let chunk_size = (side + num_threads - 1) / num_threads;
+            let chunk_size = side.div_ceil(num_threads);
             let mut values_chunks = Vec::with_capacity(num_threads);
             let mut indices_chunks = Vec::with_capacity(num_threads);
             // SAFETY: the slice here is uninitialised data; it must not be read.