message: Improve a couple comments
diff: @@ -233,8 +233,8 @@ impl<F: PrimeField> CircuitGate<F> {
  ) -> CircuitGateResult<()> {
  // Grab the relevant part of the witness
  let argument_witness = self.argument_witness(row, witness)?;
  - // Set up the constants. Note that alpha, beta, gamma and joint_combiner because this
  - // function is not running the prover.
  + // Set up the constants. Note that alpha, beta, gamma and joint_combiner
  + // are zero because this function is not running the prover.
  let constants = expr::Constants::<F> {
  alpha: F::zero(),
  beta: F::zero(),
  @@ -280,10 +280,10 @@ impl<F: PrimeField> CircuitGate<F> {
  }
  };
  - // Check for invalid constraints
  + // Check for failed constraints
  for (i, result) in results.iter().enumerate() {
  if !result.is_zero() {
  - // Pinpoint invalid constraint
  + // Pinpoint failed constraint
  return Err(CircuitGateError::InvalidConstraintNumber(self.typ, i));
  }
  }
  