chore: fix typos (#3907)

tokio-util/src/sync/cancellation_token.rs

@@ -775,8 +775,8 @@ impl CancellationTokenState {
             return Poll::Ready(());
         }
 
-        // So far the token is not cancelled. However it could be cancelld before
-        // we get the chance to store the `Waker`. Therfore we need to check
+        // So far the token is not cancelled. However it could be cancelled before
+        // we get the chance to store the `Waker`. Therefore we need to check
         // for cancellation again inside the mutex.
         let mut guard = self.synchronized.lock().unwrap();
         if guard.is_cancelled {

tokio-util/src/sync/intrusive_double_linked_list.rs

@@ -222,7 +222,7 @@ impl<T> LinkedList<T> {
         }
     }
 
-    /// Returns whether the linked list doesn not contain any node
+    /// Returns whether the linked list does not contain any node
     pub fn is_empty(&self) -> bool {
         if self.head.is_some() {
             return false;