message: add vbmul constraint to index
diff: @@ -15,7 +15,7 @@ use commitment_dlog::{
  };
  use oracle::poseidon::{ArithmeticSpongeParams};
  use plonk_15_wires_circuits::{
  - polynomials::{chacha, lookup, poseidon},
  + polynomials::{chacha, lookup, poseidon, varbasemul},
  gate::{GateType, LookupInfo, LookupsUsed},
  expr::{PolishToken, Expr, Column, Linearization},
  nolookup::constraints::{zk_w3, ConstraintSystem},
  @@ -230,7 +230,7 @@ where
  h.insert(Index(GateType::Generic));
  h
  };
  - let expr = poseidon::constraint(&cs.fr_sponge_params);
  + let expr = poseidon::constraint(&cs.fr_sponge_params) + varbasemul::constraint(super::range::MUL.start);
  let expr =
  if lookup_used.is_some() {
  expr +
  