Updated note to link to semantically-managed state

Author: ericwbailey

partials/section.forms.hbs

@@ -611,7 +611,7 @@
 
                 <h5>Notes:</h5>
                 <p>
-                    <small>Use <code>:hover</code>, <code>:focus</code>, and <code>:active</code> selectors to control the other button states. Learn more about <a rel="external noopener" href="https://medium.com/eightshapes-llc/buttons-in-design-systems-eac3acf7e23#.b1p96hsrw">Buttons in Design Systems</a>.</small>
+                    <small>Use <code>:hover</code>, <code>:focus</code>, and <code>:active</code> selectors to control the other button states. Learn more about <a rel="external noopener" href="https://css-tricks.com/user-facing-state/">semantically managing state</a> and using <a rel="external noopener" href="https://medium.com/eightshapes-llc/buttons-in-design-systems-eac3acf7e23#.b1p96hsrw">Buttons in Design Systems</a>.</small>
                 </p>
             </div><!-- End of #subsection__buttons -->
         </fieldset><!-- End of #subsection__states-and-validation -->