A typo (#5644)

It should be `useContext(AuthContext)` whereas it's `useContext(AuthProvider)`.

beta/src/content/reference/react/useContext.md

@@ -1337,7 +1337,7 @@ function MyApp() {
 }
 ```
 
-As a result of this change, even if `MyApp` needs to re-render, the components calling `useContext(AuthProvider)` won't need to re-render unless `currentUser` has changed. Read more about [`useMemo`](/reference/react/useMemo#skipping-re-rendering-of-components) and [`useCallback`.](/reference/react/useCallback#skipping-re-rendering-of-components)
+As a result of this change, even if `MyApp` needs to re-render, the components calling `useContext(AuthContext)` won't need to re-render unless `currentUser` has changed. Read more about [`useMemo`](/reference/react/useMemo#skipping-re-rendering-of-components) and [`useCallback`.](/reference/react/useCallback#skipping-re-rendering-of-components)
 
 ---