message: Update `L2WithdrawalVerifier` -> `OptimismPortal` in `withdrawals.md`
diff: @@ -22,7 +22,7 @@ more specific terms to differentiate:
  withdrawal.
  Withdrawals are initiated on L2 via a call to the Message Passer predeploy contract, which records the important
  -properties of the message in its storage. Withdrawals are finalized on L1 via a call to the `L2WithdrawalVerifier`
  +properties of the message in its storage. Withdrawals are finalized on L1 via a call to the `OptimismPortal`
  contract, which proves the inclusion of this withdrawal message.
  In this way, withdrawals are different from [deposits][g-deposits] which make use of a special transaction type in the
  