simplify an expression

Author: joseph-gio

crates/bevy_ecs/src/schedule/label.rs

@@ -187,8 +187,7 @@ impl Labels {
     /// Gets a reference to the label with specified index.
     pub fn get<L: 'static>(&self, key: u64) -> Option<LabelGuard<L>> {
         RwLockReadGuard::try_map(self.0.read(), |type_map| {
-            let set = type_map.get::<IndexSet<L>>()?;
-            set.get_index(key as usize)
+            type_map.get::<IndexSet<L>>()?.get_index(key as usize)
         })
         .ok()
     }