chore: add natspec

Author: prestwich

src/apps/Bridge.sol

@@ -7,7 +7,10 @@ import {SimpleERC20} from "simple-erc20/SimpleERC20.sol";
 import {SignetL2} from "../l2/Signet.sol";
 
 abstract contract BridgeL2 is SignetL2, SimpleERC20 {
+    /// @notice The address of the asset on the host chain.
     address immutable HOST_ASSET;
+    /// @notice The address of the bank on the host chain. The bank holds the
+    ///         asset while tokens are bridged into the rollup.
     address immutable HOST_BANK;
 
     constructor(
@@ -22,6 +25,7 @@ abstract contract BridgeL2 is SignetL2, SimpleERC20 {
         HOST_BANK = _hostBank;
     }
 
+    /// @notice Bridges assets into the rollup for a given recipient.
     function _bridgeIn(address recipient, uint256 amount, RollupOrders.Input[] memory inputs) internal virtual {
         RollupOrders.Output[] memory outputs = new RollupOrders.Output[](1);
         outputs[0] = makeHostOutput(HOST_ASSET, amount, HOST_BANK);
@@ -31,10 +35,16 @@ abstract contract BridgeL2 is SignetL2, SimpleERC20 {
         _mint(recipient, amount);
     }
 
+    /// @notice Bridges assets into the rollup for a given recipient.
     function bridgeIn(address recipient, uint256 amount) public virtual {
         _bridgeIn(recipient, amount, new RollupOrders.Input[](0));
     }
 
+    /// @notice Burn asset on L2, and create an order to bridge out asset to
+    /// L1. If the order is not filled, the asset will not be burned.
+    ///
+    /// This transaction should be paired with some off-chain logic that fills
+    /// orders from the L1 bank.
     function _bridgeOut(address recipient, uint256 amount, RollupOrders.Input[] memory inputs) internal virtual {
         RollupOrders.Output[] memory outputs = new RollupOrders.Output[](1);
         outputs[0] = makeHostOutput(HOST_ASSET, amount, recipient);
@@ -44,6 +54,11 @@ abstract contract BridgeL2 is SignetL2, SimpleERC20 {
         _burn(msg.sender, amount);
     }
 
+    /// @notice Burn asset on L2, and create an order to bridge out asset to
+    /// L1. If the order is not filled, the asset will not be burned.
+    ///
+    /// This transaction should be paired with some off-chain logic that fills
+    /// orders from the L1 bank.
     function bridgeOut(address recipient, uint256 amount) public virtual {
         _bridgeOut(recipient, amount, new RollupOrders.Input[](0));
     }