Assisticant equivalent for default WPF template selector that looks up templates using wrapped object's type

```xml
<DataTemplate DataType="{x:Type my:ItemTypeA}">
    ...
</DataTemplate>
<DataTemplate DataType="{x:Type my:ItemTypeB}">
    ...
</DataTemplate>
...
<ListBox ItemsSource="{Binding MixedList}" ItemTemplateSelector="{assisticant:DefaultSelector}" />
```