Corrected link to ajax-form library.

Closes #6465.

Author: carltongibson

docs/topics/browser-enhancements.md

@@ -81,7 +81,7 @@ was later [dropped from the spec][html5].  There remains
 as well as how to support content types other than form-encoded data.
 
 [cite]: https://www.amazon.com/RESTful-Web-Services-Leonard-Richardson/dp/0596529260
-[ajax-form]: https://github.com/encode/ajax-form
+[ajax-form]: https://github.com/tomchristie/ajax-form
 [rails]: https://guides.rubyonrails.org/form_helpers.html#how-do-forms-with-put-or-delete-methods-work
 [html5]: https://www.w3.org/TR/html5-diff/#changes-2010-06-24
 [put_delete]: http://amundsen.com/examples/put-delete-forms/