Apply suggestions from code review

Co-authored-by: Tim Deschryver <[email protected]>

Author: eps1lon

docs/react-testing-library/faq.mdx

@@ -83,7 +83,7 @@ as part of the `change` method call.
 
 <summary>How do I test error boundaries</summary>
 
-To test if an error boundary successfully catches an error, you should make sure that if the fallback of the boundary is displayed when a child threw.
+To test if an error boundary successfully catches an error, you should make sure that the fallback of the boundary is displayed when a child threw.
 
 Here's an example of how you can test an error boundary: