I'm creating a plugin to help me extend the Godot editor to let me create and edit a complex resource. The resource's data is complicated, so I can't rely on just having Godot serialize all the @exported fields the way I can with simpler resources. I came across the ResourceSaver and ResourceLoader classes and they look just like what I need to write my own loader and saver. The docs say that I can also register them through my plugin, but I can't find anything in EditorPlugin or EditorInterface that lets me register these. How do I add these to my plugin?