docs: fix broken link (#383)

Author: numb86

docs/react-testing-library/api.md

@@ -176,7 +176,7 @@ debug()
 ```
 
 This is a simple wrapper around `prettyDOM` which is also exposed and comes from
-[`DOM Testing Library`](https://github.com/testing-library/dom-testing-library/blob/master/README.md#prettydom).
+[`DOM Testing Library`](dom-testing-library/api-helpers.md#prettydom).
 
 ### `rerender`