Documentation missing for canGoBack()

Current Behavior

According to @satya164 in react-navigation/react-navigation#7814 we should use canGoBack() to guard against going back too much. If we don't, it'll result in a console.error() being emitted (red screen).

canGoBack is an undocumented feature. It's only mentioned in passing in the 'upgrading from 3.x' article where it's mentioned as a feature on the HeaderBackButton, however the function is (also?) available on the navigator object.

Expected Behavior
Typing "canGoBack" in search field in the documentation should yield this result.

How to reproduce

1. Open https://reactnavigation.org/docs
2. Type "canGoBack" in upper right search field

** Other comments **

It may make sense to reference the new documentation for canGoBack() in relation to goBack(), pop(), jumpTo(), and popToTop().

Commencez par rechercher dans la documentation les références existantes à canGoBack(), goBack(), pop(), jumpTo() et popToTop(). Ajoutez une entrée consultable pour canGoBack() qui explique sa disponibilité et son rôle de garde, avec des liens vers les méthodes de navigation associées ; le travail est terminé lorsque la recherche de canGoBack dans la documentation renvoie la nouvelle explication.