Fix typo in content/tokio/topics (#716)

Co-authored-by: Keith Miller <[email protected]>

content/tokio/topics/shutdown.md

@@ -113,7 +113,7 @@ let task1_handle = tokio::spawn(async move {
 tokio::spawn(async move {
     tokio::time::sleep(std::time::Duration::from_millis(10)).await;
 
-    // Step 4: Cancel the original or clonned token to notify other tasks about shutting down gracefully
+    // Step 4: Cancel the original or cloned token to notify other tasks about shutting down gracefully
     token.cancel();
 });