[Docs] Replace useState with edit in useEntityRecord usage examples

[adamziel]

What?

The usage example added in Add mutations data and helper functions to useEntityRecord proposes storing updates via useState. However, the new mutation helpers can store them directly in the entity record. This PR updates the example to do just that.

cc @gziolo

[gziolo]

I like the change for the example included as it promotes the API included with useEntityRecord. We need to ensure that useCallback will work correctly when the id changes that I have doubts about.

[gziolo]

Static Analysis failed - the same changes need to be applied to JSDoc comment for useEntityRecord.