Fix cargo check on examples

examples/memo_chain.rs

@@ -7,7 +7,7 @@ fn main() {
 fn app() -> Element {
     let mut value = use_signal(|| 0);
     let mut depth = use_signal(|| 0 as usize);
-    let mut items = use_memo(move || (0..depth()).map(|f| f as _).collect::<Vec<isize>>());
+    let items = use_memo(move || (0..depth()).map(|f| f as _).collect::<Vec<isize>>());
 
     let state = use_memo(move || value() + 1);