Whether the page can be popped from navigation stack.
Set it to FALSE to disable shortcuts and gestures, as well as remove the back button from class@HeaderBar.
Manually calling adw.navigation_view.NavigationView.pop or using the navigation.pop action will still work.
See property@HeaderBar:show-back-button for removing only the back button, but not shortcuts.
Builder instance for fluent chaining
Set canPop property.