message: docs: reentrancy protection comment on L2 messenger
diff: @@ -95,6 +95,9 @@ contract L2CrossDomainMessenger is IL2CrossDomainMessenger {
  bytes memory _message,
  uint256 _messageNonce
  ) public {
  + // Since it is impossible to deploy a contract to an address on L2 which matches
  + // the alias of the L1CrossDomainMessenger, this check can only pass when it is called in
  + // the first call from of a deposit transaction. Thus reentrancy is prevented here.
  require(
  AddressAliasHelper.undoL1ToL2Alias(msg.sender) == l1CrossDomainMessenger,
  "Provided message could not be verified."
  