docs(world): fix minor bugs in the world docs (#1115)

Co-authored-by: alvarius <[email protected]>

docs/pages/world/world-101.mdx

@@ -222,19 +222,29 @@ Now we can import our new table, and write something to it. Let’s write a func
 // SPDX-License-Identifier: MIT
 pragma solidity >=0.8.0;
 import { System } from "@latticexyz/world/src/System.sol";
-import { Dog } from "../codegen/tables/Dog.sol"; // import table we created
+import { Dog, DogData } from "../codegen/tables/Dog.sol"; // import table we created
 contract MySystem is System {
   function addEntry(string memory name, string memory color) public returns (bytes32) {
     bytes32 key = bytes32(abi.encodePacked(block.number, msg.sender, gasleft())); // creating a random key for the record
     address owner = _msgSender(); // IMPORTANT: always refer to the msg.sender using the _msgSender() function
-    Dog.set(key, {owner: owner, name: name, color: color}); // creating our record!
+    Dog.set(key, DogData({owner: owner, name: name, color: color})); // creating our record!
     return key;
   }
 }
 ```
 
 That’s it! `MySystem`, just like `IncrementSystem`, will have access to Dog given they are in the same namespace.
 
+
+We can run `pnpm mud worldgen` in the contract folder to recreate the systems.
+
+```bash
+> pnpm mud worldgen
+Generated system interface: src/codegen/world/IIncrementSystem.sol
+Generated system interface: src/codegen/world/IMySystem.sol
+Generated system interface: src/codegen/world/IWorld.sol
+```
+
 After this step, the filesystem of the World is like this:
 
 ```bash