fix: readme and examples syntax

examples/web/async_web.rs

@@ -16,7 +16,7 @@ struct DogApi {
     message: String,
 }
 
-static APP: Component<()> = |(cx, _props)| {
+static APP: Component = |(cx, _props)| {
     let state = use_state(&cx, || 0);
 
     const ENDPOINT: &str = "https://dog.ceo/api/breeds/image/random/";