Use allow-reachable delegatecall in Multicall (#3970)

contracts/utils/Multicall.sol

@@ -13,8 +13,8 @@ import "./Address.sol";
 abstract contract Multicall {
     /**
      * @dev Receives and executes a batch of function calls on this contract.
+     * @custom:oz-upgrades-unsafe-allow-reachable delegatecall
      */
-    /// @custom:oz-upgrades-unsafe-allow delegatecall
     function multicall(bytes[] calldata data) external virtual returns (bytes[] memory results) {
         results = new bytes[](data.length);
         for (uint256 i = 0; i < data.length; i++) {