fix within link (#794)

Author: edag94

docs/queries/about.mdx

@@ -175,7 +175,7 @@ All of the queries exported by DOM Testing Library accept a `container` as the
 first argument. Because querying the entire `document.body` is very common, DOM
 Testing Library also exports a `screen` object which has every query that is
 pre-bound to `document.body` (using the
-[`within`](/docs/dom-testing-library/api-helpers#within-and-getqueriesforelement-apis)
+[`within`](dom-testing-library/api-within.mdx)
 functionality). Wrappers such as React Testing Library re-export `screen` so you
 can use it the same way.