Snackbar DeactivateStoryboardCompletedEvent Bug

Nobody has claimed this yet.

I think this is a bug...

**.../MaterialDesignThemes.Wpf/Snackbar.cs**

```

public static readonly RoutedEvent DeactivateStoryboardCompletedEvent = EventManager.RegisterRoutedEvent(
nameof(DeactivateStoryboardCompleted), RoutingStrategy.Bubble, typeof(SnackbarMessageEventArgs), typeof(Snackbar));

public event RoutedPropertyChangedEventHandler DeactivateStoryboardCompleted
{
add => AddHandler(DeactivateStoryboardCompletedEvent, value);
remove => RemoveHandler(DeactivateStoryboardCompletedEvent, value);
}

private static void OnDeactivateStoryboardCompleted(IInputElement snackbar, SnackbarMessage message)
{
var args = new SnackbarMessageEventArgs(DeactivateStoryboardCompletedEvent, message);
snackbar.RaiseEvent(args);
}

```

Prompt type mismatch when I register events...

I didn't look at all the code. Maybe it's right?

```

public static readonly RoutedEvent DeactivateStoryboardCompletedEvent = EventManager.RegisterRoutedEvent(
nameof(DeactivateStoryboardCompleted), RoutingStrategy.Bubble, typeof(RoutedPropertyChangedEventHandler), typeof(Snackbar));

public event RoutedPropertyChangedEventHandler DeactivateStoryboardCompleted
{
add => AddHandler(DeactivateStoryboardCompletedEvent, value);
remove => RemoveHandler(DeactivateStoryboardCompletedEvent, value);
}

private static void OnDeactivateStoryboardCompleted(IInputElement snackbar, SnackbarMessage message)
{
var snackbarMessageEventArgs = new SnackbarMessageEventArgs(DeactivateStoryboardCompletedEvent, snackbar, message);
var args = new RoutedPropertyChangedEventArgs(snackbarMessageEventArgs, snackbarMessageEventArgs, DeactivateStoryboardCompletedEvent);
snackbar.RaiseEvent(args);
}

```

Start in MaterialDesignThemes.Wpf/Snackbar.cs and inspect the DeactivateStoryboardCompleted event registration, delegate declaration, and OnDeactivateStoryboardCompleted call together. Check the WPF routed-event types involved and build the project to confirm the reported type mismatch is resolved without introducing another event-signature error.

Written by the indexing model from the issue text.