Singleton type is unable to call to_display_text

```ruby
type Singleton_Type
    some_method self = "some"
    to_display_text self = "here"

main =
    any1 = Singleton_Type
    any3 = any1.to_display_text
    any2 = any1.some_method
```

<img width="1178" height="546" alt="Image" src="https://github.com/user-attachments/assets/cdbb6e85-b3c3-42cd-86f4-321dd5f04c44" />