Use the covariant return type feature of C# 9 to allow method overrides to be more specific about their return type. By exposing this information, e.g. for Widget.Clone(), callers will have more information. This allows various casts to be removed as the information is now available within the type system.
- Add prefixes to all message keys to provide context
- Use messages with attributes for some UI elements (dropdowns, dialogs, checkboxes, menus)
- Rename some class fields for consistency with translation keys
