Update react.mdx (#850)

Replacing dead link for `aria-label` with a working one.

Author: jirihofman

docs/content/packages/react.mdx

@@ -129,4 +129,4 @@ can pass it either via the `icon` prop, or as the only child:
 [npm]: https://www.npmjs.com/
 [install-npm]: https://docs.npmjs.com/getting-started/installing-node
 [tree-shaking]: https://developer.mozilla.org/en-US/docs/Glossary/Tree_shaking
-[aria-label]: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/ARIA_Techniques/Using_the_aria-label_attribute
+[aria-label]: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-label