Improve Angular Testing Library API documentation

I am new to Angular Testing and stumbled across some misunderstandings while writing my first tests. I would like to help you improve it, so let's start collecting the issues. 🙂

1. The example for the declarations (within RenderOptions) is wrong. It configures the providers. Furthermore there is no descriptions for the providers option. https://testing-library.com/docs/angular-testing-library/api#declarations
2. We might also add a note which of the RenderOptions are passed to the Angular TestBed. Or even separate those from the added render properties.
3. Explaining that this library still works with the core testing functionality of Angular under the hood will also help to implement non-standard situations. For example in one test I needed to interact with a service. This can be done with the Angular TestBed: TestBed.get(TargetService).init();

リンク先の RenderOptions ページにある Angular Testing Library API ドキュメントから始めてください。declarations の例を確認し、不足している providers の説明を追加して、どのオプションが Angular TestBed に渡されるのか、また TestBed が標準外のケースをどのようにサポートできるのかを明確にしてください。例と説明用の注記でこれらの点が正確にカバーされていれば完了です。