This makes it easier to spot syntax errors when editing the class reference. The schema is referenced locally so validation can still work offline. Each class XML's schema conformance is also checked on GitHub Actions.
VideoPlayer
VideoStreamPlayer
It's a player for `VideoStream` resources, just like `AudioStreamPlayer` is a player for `AudioStream` resources. Closes https://github.com/godotengine/godot-proposals/issues/3624.
