feat(docs): Improved shared state, use_effect and use_memo docs

docs/guide/src/en/async/use_effect.md

@@ -0,0 +1,32 @@
+# UseEffect
+
+[`use_effect`](https://docs.rs/dioxus-hooks/latest/dioxus_hooks/fn.use_effect.html) provides a future that executes after the hooks have been applied.
+
+Whenever the hooks dependencies change, the future will be re-evaluated. This is useful to syncrhonize with external events.
+
+If a future is pending when the dependencies change, the previous future will be allowed to continue
+
+> The `dependencies` is tuple of references to values that are `PartialEq + Clone`.
+
+```rust, no_run
+#[inline_props]
+fn Profile(cx: Scope, id: &str) -> Element {
+    let name = use_state(cx, || "Default name");
+
+    // Only fetch the user data when the id changes.
+    use_effect(cx, (id,), |(id,)| async move {
+        let user = fetch_user(id).await;
+        name.set(user.name);
+    });
+
+    render!(
+        p { "{name}" }
+    )
+}
+
+fn app(cx: Scope) -> Element {
+    render!(
+        Profile { id: "dioxusLabs" }
+    )
+}
+```