message: Fix uiWorker configuration at data fetching doc
diff: @@ -31,8 +31,10 @@ export const App = () => {
  It's required to pass `fetch` function to `uiWorker`:
  ```javascript
  +const handler = uiWorker({ yoga, fetch });
  +
  onmessage = event => {
  - uiWorker({ yoga, fetch })(event);
  + handler(event);
  };
  ```
  