iris: move text state into shared resources

readme.md

@@ -59,7 +59,7 @@ the retained widget tree dirty:
 ```rust
 rsc.spawn_task(async move |mut ctx| {
     let text = load_text().await;
-    ctx.update(move |_, rsc| label.edit(rsc).set(&text));
+    ctx.update(move |_, rsc| label(rsc).set(&text));
 });
 ```