Update src/part-guide/adv-async-await.md

Co-authored-by: Travis Cross <[email protected]>

src/part-guide/adv-async-await.md

@@ -13,7 +13,7 @@ async fn test_something() {
 
 There are many ways to configure the test, see the [docs](https://docs.rs/tokio/latest/tokio/attr.test.html) for details.
 
-There are some more advanced topics in testing async code (e.g., testing for race conditions, deadlock, etc.) and we'll cover some of those [later]() in this guide.
+There are some more advanced topics in testing async code (e.g., testing for race conditions, deadlock, etc.), and we'll cover some of those [later]() in this guide.
 
 
 ## Blocking and cancellation