Update docs

test/utils/cryptography/MessageHashUtils.t.sol

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.20;
+
+import {Test} from "forge-std/Test.sol";
+import {MessageHashUtils} from "@openzeppelin/contracts/utils/cryptography/MessageHashUtils.sol";
+
+contract MessageHashUtilsTest is Test {
+    function testToDataWithIntendedValidatorHash(address validator, bytes memory data) external pure {
+        assertEq(
+            MessageHashUtils.toDataWithIntendedValidatorHash(validator, data),
+            MessageHashUtils.toDataWithIntendedValidatorHash(_dirty(validator), data)
+        );
+    }
+
+    function testToDataWithIntendedValidatorHash(address validator, bytes32 messageHash) external pure {
+        assertEq(
+            MessageHashUtils.toDataWithIntendedValidatorHash(validator, messageHash),
+            MessageHashUtils.toDataWithIntendedValidatorHash(_dirty(validator), messageHash)
+        );
+
+        assertEq(
+            MessageHashUtils.toDataWithIntendedValidatorHash(validator, messageHash),
+            MessageHashUtils.toDataWithIntendedValidatorHash(validator, abi.encodePacked(messageHash))
+        );
+    }
+
+    function _dirty(address input) private pure returns (address output) {
+        assembly ("memory-safe") {
+            output := or(input, shl(160, not(0)))
+        }
+    }
+}