emit previous delay

src/root/flowrate/FlowRateWithdrawalQueue.sol

@@ -66,7 +66,7 @@ abstract contract FlowRateWithdrawalQueue {
     );
 
     // Indicates that the new withdrawal delay.
-    event WithdrawalDelayUpdated(uint256 delay);
+    event WithdrawalDelayUpdated(uint256 delay, uint256 previousDelay);
 
     // // A withdrawal was being processed, but the index is outside of the array.
     error IndexOutsideWithdrawalQueue(uint256 lengthOfQueue, uint256 requestedIndex);
@@ -95,8 +95,9 @@ abstract contract FlowRateWithdrawalQueue {
      * @param delay Withdrawal delay in seconds.
      */
     function _setWithdrawalDelay(uint256 delay) internal {
+        uint256 previousDelay = withdrawalDelay;
         withdrawalDelay = delay;
-        emit WithdrawalDelayUpdated(delay);
+        emit WithdrawalDelayUpdated(delay, previousDelay);
     }
 
     /**

src/root/flowrate/RootERC20BridgeFlowRate.sol

@@ -100,9 +100,8 @@ contract RootERC20BridgeFlowRate is
 
     /**
      * @notice Set the time in the queue for queued withdrawals.
-     * @param delay The number of seconds between when the ExitHelper is called to
-     *         complete a crosschain transfer and when finaliseHeldTransfers can be
-     *         called.
+     * @param delay The number of seconds between when the AxelarAdapter is called to
+     *         complete a crosschain transfer.
      * @dev Only RATE role.
      * NOTE: There is no range checking on delay. Delay could be inadvertently be set to
      *       a very large value, representing a large delay. If this is done, the withdrawal
@@ -172,7 +171,7 @@ contract RootERC20BridgeFlowRate is
      *         - withdrawer: Account that initiated the transfer on the child chain.
      *         - receiver: Account to transfer tokens to.
      *         - amount: The number of tokens to transfer.
-     * @dev Called by the ExitHelper.
+     * @dev Called by the AxelarAdapter.
      *      Only when not paused.
      */
     function _withdraw(bytes memory data) internal override {