docs: Fix c&p typos (checked -> expanded) (#732)

Author: tonyhallett

docs/dom-testing-library/api-queries.mdx

@@ -837,9 +837,9 @@ For example in
 ```
 
 you can get the "Expandable Menu Item" link by calling
-`getByRole('link', { expanded: false })`. To learn more about the checked state
+`getByRole('link', { expanded: false })`. To learn more about the expanded state
 and which elements can have this state see
-[ARIA `aria-checked`](https://www.w3.org/TR/wai-aria-1.2/#aria-expanded).
+[ARIA `aria-expanded`](https://www.w3.org/TR/wai-aria-1.2/#aria-expanded).
 
 ```html
 <div role="dialog">...</div>