Type checking nested navigator is missing StackParamList definition and usage

[dlee]

In the Nesting Navigators guide, the example given does not work with the stack structure provided in the page (which is not nested to begin with). I believe the author is implying a different nested stack (since the example is using StackParamList instead of RootStackParamList), but the definition for the StackParamList is not provided, confusing the reader into thinking it's the same as the RootStackParamList.

The definition of StackParamList and its usage should provided to give context to the nested examples.