Update part5b.md

Added new link for Refs since react docs has been updated and the old documentation directs us to the new link.

Author: FurkanCodes

src/content/5/en/part5b.md

@@ -361,7 +361,7 @@ Our current implementation is quite good; it has one aspect that could be improv
 
 After a new note is created, it would make sense to hide the new note form. Currently, the form stays visible. There is a slight problem with hiding the form. The visibility is controlled with the <i>visible</i> variable inside of the <i>Togglable</i> component. How can we access it outside of the component?
 
-There are many ways to implement closing the form from the parent component, but let's use the [ref](https://reactjs.org/docs/refs-and-the-dom.html) mechanism of React, which offers a reference to the component.
+There are many ways to implement closing the form from the parent component, but let's use the [ref](https://react.dev/learn/referencing-values-with-refs) mechanism of React, which offers a reference to the component.
 
 Let's make the following changes to the <i>App</i> component: