It's nice to sometimes use the RawEditor to edit something and then
later you want to see what it looks, and having to switch to the
Markdown Editor for that is very annoying.
Make it a ChageNotifier and try to access it through the Provider
instead of like a global variable. This way, the state is better
managed and it'll be easier to split out Settings into smaller classes.
That way we don't need to toggle it each time.
Maybe it would be nice to have this exposed via the settings as well,
per editor. So I could enable it / disable it per editor.
