message: add doc string for srs
diff: @@ -238,6 +238,7 @@ impl<G: CommitmentCurve> VerifierIndex<G>
  where
  G::BaseField: PrimeField,
  {
  + /// Gets srs from [VerifierIndex] lazily
  pub fn srs(&self) -> &Arc<SRS<G>> {
  self.srs.get_or_init(|| {
  let mut srs = SRS::<G>::create(self.max_poly_size);
  