message: docs(ref-type): remove outdated comments
diff: @@ -29,7 +29,6 @@ class Cat {
  @prop()
  public name: string;
  - // Use `ref` for arrays too
  @prop({ ref: 'Kitten' })
  public babies?: Ref<Kitten>[];
  }
  @@ -42,7 +41,6 @@ class Person {
  @prop()
  public name: string;
  - // Use `ref` for single items
  @prop({ ref: 'Cat' })
  public pet?: Ref<Cat>;
  }
  