Update docs

contracts/mocks/token/ERC20VotesAdditionalCheckpointsMock.sol

@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
+
+import {ERC20Votes} from "../../token/ERC20/extensions/ERC20Votes.sol";
+import {VotesExtended, Votes} from "../../governance/utils/VotesExtended.sol";
+import {SafeCast} from "../../utils/math/SafeCast.sol";
+
+abstract contract ERC20VotesExtendedMock is ERC20Votes, VotesExtended {
+    function _delegate(address account, address delegatee) internal virtual override(Votes, VotesExtended) {
+        return super._delegate(account, delegatee);
+    }
+
+    function _transferVotingUnits(
+        address from,
+        address to,
+        uint256 amount
+    ) internal virtual override(Votes, VotesExtended) {
+        return super._transferVotingUnits(from, to, amount);
+    }
+}
+
+abstract contract ERC20VotesExtendedTimestampMock is ERC20VotesExtendedMock {
+    function clock() public view virtual override returns (uint48) {
+        return SafeCast.toUint48(block.timestamp);
+    }
+
+    // solhint-disable-next-line func-name-mixedcase
+    function CLOCK_MODE() public view virtual override returns (string memory) {
+        return "mode=timestamp";
+    }
+}