Docs: update ref callback behaviour (#7927)

Author: ninamma

src/content/learn/manipulating-the-dom-with-refs.md

@@ -211,7 +211,7 @@ This is because **Hooks must only be called at the top-level of your component.*
 
 One possible way around this is to get a single ref to their parent element, and then use DOM manipulation methods like [`querySelectorAll`](https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelectorAll) to "find" the individual child nodes from it. However, this is brittle and can break if your DOM structure changes.
 
-Another solution is to **pass a function to the `ref` attribute.** This is called a [`ref` callback.](/reference/react-dom/components/common#ref-callback) React will call your ref callback with the DOM node when it's time to set the ref, and with `null` when it's time to clear it. This lets you maintain your own array or a [Map](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map), and access any ref by its index or some kind of ID.
+Another solution is to **pass a function to the `ref` attribute.** This is called a [`ref` callback.](/reference/react-dom/components/common#ref-callback) React will call your ref callback with the DOM node when it's time to set the ref, and call the cleanup function returned from the callback when it's time to clear it. This lets you maintain your own array or a [Map](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map), and access any ref by its index or some kind of ID.
 
 This example shows how you can use this approach to scroll to an arbitrary node in a long list: