Wrong Collections ObservableGroup C# sample code

[joseborges]

Not sure anyone already reported this, but there's wrong sample code on the Collections ObservableGroup C# sample code page, like this:

[michael-hawker]

🦙 It needs to be updated here: https://github.com/CommunityToolkit/MVVM-Samples/blob/master/samples/MvvmSampleUwp/Views/CollectionsPage.xaml#L139-L159

With the code from here: https://github.com/CommunityToolkit/MVVM-Samples/blob/master/samples/MvvmSample.Core/ViewModels/Widgets/ContactsListWidgetViewModel.cs