Add missing whitespace (#2610)

content/docs/concurrent-mode-reference.md

@@ -126,7 +126,7 @@ The `useTransition` hook returns two values in an array.
 **If some state update causes a component to suspend, that state update should be wrapped in a transition.**
 
 ```js
-const SUSPENSE_CONFIG = {timeoutMs: 2000 };
+const SUSPENSE_CONFIG = { timeoutMs: 2000 };
 
 function App() {
   const [resource, setResource] = useState(initialResource);