Allow setting a displayName for wrapper component created in renderHook

[vikr01]

What:

• Adding a displayName so that if you try to inspect the wrapper component renderHook creates, you can (i.e. console.log, useFiber, ReactCurrentOwner)

Why:

• It's a simple change and makes debugging smoother for those who need it

How:

Checklist:

• Documentation added to the
  docs site
• Tests
• TypeScript definitions updated
• Ready to be merged
  

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit 443834a:

Sandbox	Source
react-testing-library-examples	Configuration

[MatanBobi]

Thanks for this.
My main concern with this PR is that people might use it and assert on it for some reason. What's the real benefit you get from seeing the display name here? E.g. what's the use case where you felt like you need it?

[vikr01]

For hooks that use the internal fiber nodes, such as https://github.com./pmndrs/its-fine, when you check the react tree, you'd want to see a name you're familiar with otherwise it's just going to be null.

https://github.com./pmndrs/its-fine/blob/main/src/index.test.tsx#L146

In my specific use case, I'm creating a hook that gives you a string that is unique to the structure of an element, so that you can restore values based on its position (i.e. after suspending). So in this scenario, I want this actual displayName string because the pointer for the component is destroyed.

https://github.com./vikr01/react-suspense-tools/blob/initial_build/packages/useStructuralId/src/__tests__/__snapshots__/useStructuralId.test.tsx.snap#L3

So yes, it is something you would want to assert on, but you can only assert on it if you're able to reach the component by attempting to see the element tree.