Fix guides for 5.0 (#4654)

Co-authored-by: Ernesto García <ernestognw@gmail.com>
(cherry picked from commit e12511b53e)

docs/modules/ROOT/pages/access-control.adoc

@@ -9,24 +9,9 @@ The most common and basic form of access control is the concept of _ownership_:
 
 OpenZeppelin Contracts provides xref:api:access.adoc#Ownable[`Ownable`] for implementing ownership in your contracts.
 
-[source,solidity]
-----
-// contracts/MyContract.sol
-// SPDX-License-Identifier: MIT
-pragma solidity ^0.8.20;
-
-import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
-
-contract MyContract is Ownable {
-    function normalThing() public {
-        // anyone can call this normalThing()
-    }
-
-    function specialThing() public onlyOwner {
-        // only the owner can call specialThing()!
-    }
-}
-----
+```solidity
+include::api:example$MyContractOwnable.sol[]
+```
 
 By default, the xref:api:access.adoc#Ownable-owner--[`owner`] of an `Ownable` contract is the account that deployed it, which is usually exactly what you want.