message: README: update to non-recursive APIs
diff: @@ -52,18 +52,8 @@ let verifier_index = prover_index.verifier_index();
  // create a proof
  let group_map = <Affine as CommitmentCurve>::Map::setup();
  -let proof = {
  - // for recursion
  - let k = ceil_log2(index.srs.g.len());
  - let chals: Vec<_> = (0..k).map(|_| Fp::rand(rng)).collect();
  - let comm = {
  - let coeffs = b_poly_coefficients(&chals);
  - let b = DensePolynomial::from_coefficients_vec(coeffs);
  - index.srs.commit_non_hiding(&b, None)
  - };
  - (chals, comm)
  - ProverProof::create::<BaseSponge, ScalarSponge>(&group_map, witness, &prover_index, vec![prev])
  -};
  +let proof = ProverProof::create::<BaseSponge, ScalarSponge>(
  + &group_map, witness, &prover_index);
  // verify a proof
  verify::<Affine, BaseSponge, ScalarSponge>(&group_map, verifier_index, proof).unwrap();
  