chore: use TS generics for BottomTab types

[tjaniczek]

Summary

This PR switches BottomNavigation implementation to use generic type instead of hardcoded Route.

Due to the fact that BottomNavigation.Bar may be used with any router, we should not force users to adhere to Material's generic default types. As long as all methods passed to BottomNavigation.Bar are type safe the user should be able to define (or import from chosen router) the type himself.

This change is also required as a preparation for integration with React Navigation 7, that has two breaking changes related to MaterialBottomTabView:

• removal of useLinkBuilder
• removal of key in onTabPress events

There should be no changes to JS users. For TS users BottomNavigation should now correctly infer types in handlers (onTabPress, getLabelText and so on) - but if they used custom Route type previously - they had to disable type checking in their code anyway 🤷

Tested in both React Native 6 & 7, docs updated, added test to document the behaviour.

Test plan

It would be nice to install it on real-world app and see if everything works as expected.

[github-actions]

The mobile version of example app from this branch is ready! You can see it here.

[callstack-bot]

Hey @tjaniczek, thank you for your pull request 🤗. The documentation from this branch can be viewed here.

[tjaniczek]

State for now:

• BottomNavigation allows custom state and properly infers Route state from the passed props
• BottomNavigation.Bar allows custom state and properly infers Route state from the passed props
• passing explicit Route shape is available when automatic inference is not possible
• above behaviour documented in docs
• works in RN6 & RN7.0.0-alpha.1 (with small change useLinkBuilder -> useLinkTools)
• added test to check custom Route shape

[lukewalczak]

The ultimate goal for new docs is to introduce tabs JS and TS similar to npm and yarn so users can switch between those two and check which fit more for them.

cc: @DimitarNestorov (as far as I remember you were asking for that)

At the moment, since it's not available, maybe we can take advantage of my other PR introducing "More Examples" , wdyt?

[tjaniczek]

Agreed, will change it as soon as Portal docs land in main 👍

[tjaniczek]

Done: https://snack.expo.dev/@react-native-paper/bottomnavigation---usage-with-typescript

Please note that this snack will show warning at the moment, since this change is not merged yet. We'll need to update dependency in the snack when this change gets released 👍