Update referenced for private state variables to leave alone in Preview macro

Trying this agent skill out, I agree with proper access control modifiers on `@State var awesomeNamedProperty: String` --> `@State private var awesomeNamedProperty: String`. Using the agent skill, and asking the agent to add private to all of the state properties if found in review worked great! Except it didn't compile. `@Previewable @State var previewOnlyProperty: String` cannot be made private. Please update the skill to provide this knowledge to the agents that don't yet know about `@Previewable`.