Update docs

contracts/access/AccessControlCrossChain.sol

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+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v4.6.0) (access/AccessControlCrossChain.sol)
+
+pragma solidity ^0.8.4;
+
+import "./AccessControl.sol";
+import "../crosschain/CrossChainEnabled.sol";
+
+/**
+ * @dev An extension to {AccessControl} with support for cross-chain access management.
+ * For each role, is extension implements an equivalent "aliased" role that is used for
+ * restricting calls originating from other chains.
+ *
+ * For example, if a function `myFunction` is protected by `onlyRole(SOME_ROLE)`, and
+ * if an address `x` has role `SOME_ROLE`, it would be able to call `myFunction` directly.
+ * A wallet or contract at the same address on another chain would however not be able
+ * to call this function. In order to do so, it would require to have the role
+ * `_crossChainRoleAlias(SOME_ROLE)`.
+ *
+ * This aliasing is required to protect against multiple contracts living at the same
+ * address on different chains but controlled by conflicting entities.
+ *
+ * _Available since v4.6._
+ */
+abstract contract AccessControlCrossChain is AccessControl, CrossChainEnabled {
+    bytes32 public constant CROSSCHAIN_ALIAS = keccak256("CROSSCHAIN_ALIAS");
+
+    /**
+     * @dev See {AccessControl-_checkRole}.
+     */
+    function _checkRole(bytes32 role) internal view virtual override {
+        if (_isCrossChain()) {
+            _checkRole(_crossChainRoleAlias(role), _crossChainSender());
+        } else {
+            super._checkRole(role);
+        }
+    }
+
+    /**
+     * @dev Returns the aliased role corresponding to `role`.
+     */
+    function _crossChainRoleAlias(bytes32 role) internal pure virtual returns (bytes32) {
+        return role ^ CROSSCHAIN_ALIAS;
+    }
+}