Docs: Fix broken hint-axe README.md links

hint-axe docs are now generated at build time so the relative path is only good for post build local install of the repository and results in 404s for anyone browsing github or npmjs.org (the more common scenario).

To give the best experience for the more common scenario this change directs the links to webhint.io which will have the information from the latest release.

Follow-up to #3937 
Fixes #3792

Author: johnemau

Diff for: packages/hint-axe/README.md

@@ -175,18 +175,18 @@ your project.
 [wai]: https://www.w3.org/WAI/intro/accessibility.php
 [wcag 2.1]: https://www.w3.org/TR/WCAG21/
 <!-- start hint links -->
-[axe/aria]: ./docs/aria.md
-[axe/color]: ./docs/color.md
-[axe/forms]: ./docs/forms.md
-[axe/keyboard]: ./docs/keyboard.md
-[axe/language]: ./docs/language.md
-[axe/name-role-value]: ./docs/name-role-value.md
-[axe/other]: ./docs/other.md
-[axe/parsing]: ./docs/parsing.md
-[axe/semantics]: ./docs/semantics.md
-[axe/sensory-and-visual-cues]: ./docs/sensory-and-visual-cues.md
-[axe/structure]: ./docs/structure.md
-[axe/tables]: ./docs/tables.md
-[axe/text-alternatives]: ./docs/text-alternatives.md
-[axe/time-and-media]: ./docs/time-and-media.md
+[axe/aria]: https://webhint.io/docs/user-guide/hints/hint-axe/aria/
+[axe/color]: https://webhint.io/docs/user-guide/hints/hint-axe/color/
+[axe/forms]: https://webhint.io/docs/user-guide/hints/hint-axe/forms/
+[axe/keyboard]: https://webhint.io/docs/user-guide/hints/hint-axe/keyboard/
+[axe/language]: https://webhint.io/docs/user-guide/hints/hint-axe/language/
+[axe/name-role-value]: https://webhint.io/docs/user-guide/hints/hint-axe/name-role-value/
+[axe/other]: https://webhint.io/docs/user-guide/hints/hint-axe/other/
+[axe/parsing]: https://webhint.io/docs/user-guide/hints/hint-axe/parsing/
+[axe/semantics]: https://webhint.io/docs/user-guide/hints/hint-axe/semantics/
+[axe/sensory-and-visual-cues]: https://webhint.io/docs/user-guide/hints/hint-axe/sensory-and-visual-cues/
+[axe/structure]: https://webhint.io/docs/user-guide/hints/hint-axe/structure/
+[axe/tables]: https://webhint.io/docs/user-guide/hints/hint-axe/tables/
+[axe/text-alternatives]: https://webhint.io/docs/user-guide/hints/hint-axe/text-alternatives/
+[axe/time-and-media]: https://webhint.io/docs/user-guide/hints/hint-axe/time-and-media/
 <!-- end hint links -->