EventToCommand in this MVVM Toolkit

Hey!

We're migrating our WPF solution to core and noticed that the Galasoft MVVM Toolkit seems to have been superseded by this one. One problem that came up is how to express this kind of example ..

```
xmlns:cmd="clr-namespace:GalaSoft.MvvmLight;assembly=GalaSoft.MvvmLight"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"

```

in this new framework. There is a [sample in the docs](https://github.com/CommunityToolkit/MVVM-Samples/blob/master/docs/mvvm/PuttingThingsTogether.md#subreddit-selector) that uses a `interactions` namespace but never explains where this namespace comes from (probably it's not even WPF). Also there doesn't seem to be a WPF sample app.

Is WPF even supported? If so, how can we do this kind of thing?

Thanks!