Chore: some cleanup and documentation

packages/core/examples/borrowed.rs

@@ -39,6 +39,7 @@ fn app(ctx: Context<Props>) -> VNode {
                     .item_handler(Callback(set_val.clone()))
                     .build(),
                 None,
+                &[],
             ));
         }
         root.finish()

packages/core/examples/nested.rs

@@ -19,6 +19,7 @@ static Header: FC<()> = |ctx| {
                 Bottom,
                 (),
                 None,
+                &[],
             ))))
             .finish()
     }))