contracts: Fix OZ-L-05 Warn about trapped funds

packages/contracts-bedrock/contracts/L1/L1StandardBridge.sol

@@ -118,7 +118,9 @@ contract L1StandardBridge is StandardBridge {
 
     /**
      * @custom:legacy
-     * @notice Deposits some amount of ETH into a target account on L2.
+     * @notice Deposits some amount of ETH into a target account on L2. Note that if ETH is sent to
+     *         a contract on L2 and the call fails, then that ETH will be locked in the
+     *         L2StandardBridge.
      *
      * @param _to          Address of the recipient on L2.
      * @param _minGasLimit Minimum gas limit for the deposit message on L2.

packages/contracts-bedrock/contracts/L2/L2StandardBridge.sol

@@ -106,7 +106,9 @@ contract L2StandardBridge is StandardBridge {
 
     /**
      * @custom:legacy
-     * @notice Initiates a withdrawal from L2 to L1 to a target account on L1.
+     * @notice Initiates a withdrawal from L2 to L1 to a target account on L1. Note that if ETH is
+     *         sent to a contract on L1 and the call fails, then that ETH will be locked in the
+     *         L1StandardBridge.
      *
      * @param _l2Token     Address of the L2 token to withdraw.
      * @param _to          Recipient account on L1.
@@ -121,6 +123,7 @@ contract L2StandardBridge is StandardBridge {
         uint32 _minGasLimit,
         bytes calldata _data
     ) external payable virtual {
+        // TODO: add onlyEOA check on ETH withdrawals to match L1Bridge.depositETHTo?
         _initiateWithdrawal(_l2Token, msg.sender, _to, _amount, _minGasLimit, _data);
     }
 

packages/contracts-bedrock/contracts/universal/StandardBridge.sol

@@ -139,7 +139,8 @@ abstract contract StandardBridge {
     }
 
     /**
-     * @notice Send ETH to a specified account on the remote domain
+     * @notice Send ETH to a specified account on the remote domain. Note that if ETH is sent to a
+     *         contract and the call fails, then that ETH will be locked in the other bridge.
      */
     function bridgeETHTo(
         address _to,