feat(queries): Add docs about byRole#hidden

Author: eps1lon

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

@@ -533,6 +533,7 @@ getByRole(
   role: TextMatch,
   options?: {
     exact?: boolean = true,
+    hidden?: boolean = false,
     normalizer?: NormalizerFn,
   }): HTMLElement
 ```
@@ -544,6 +545,12 @@ attribute. The
 [W3C HTML recommendation](https://www.w3.org/TR/html5/index.html#contents) lists
 all HTML elements with their default aria roles.
 
+If you set `hidden` to `true` elements that are normally excluded from the
+accessibility tree are considered for the query as well. The default behavior
+follows https://www.w3.org/TR/wai-aria-1.2/#tree_exclusion with the exception of
+`role="none"` and `role="presentation"` which are considered in the query in any
+case.
+
 ```html
 <div role="dialog">...</div>
 ```