Fix for #25333

This updates the documented usage example for the @wordpress/block-editor docs to avoid showing the following error in the console

Warning: State updates from the useState() and useReducer() Hooks don't support the second callback

This is happening because onInput and onChange handlers are called with x2 args:

1. Blocks
2. Selection ranges.

Supplying the useState hook's update handler (ie: updateBlocks) as the callback causes it to be called with the two arguments applied to it. Unfortunately useState only expects a single argument which results in the error shown above.

This PR updates to docs to use an arrow function to ensure only a single argument is passed to the setState call which fixes the error. We could get fancy with partial application but for the purposes of documentation, a wrapper function is probably the easiest to understand.

How has this been tested?

You can verify two args are provided to onInput and onChange in the associated tests for the relevant components:

Other than that you'd have to test up a test environment which I haven't had the chance to do.

Types of changes

Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR.