Set up tracing docs page: indicate that the root component needs to be wrapped

[alwx]

Here is the page: https://docs.sentry.io/platforms/react-native/tracing/

The problem here is that in order to know that the root component needs to be wrapped you actually need to open another page: https://docs.sentry.io/platforms/react-native/tracing/instrumentation/automatic-instrumentation/

We can fix it by indicating that the root component needs to be wrapped on the root page as well.

[linear-code]

RN-671