Update aria of toggle

Author: rjzupkoii

_includes/masthead.html

@@ -16,7 +16,7 @@
             <li class="masthead__menu-item"><a href="{{ domain }}{{ link.url }}">{{ link.title }}</a></li>
           {% endfor %}
           <li id="theme-toggle" class="masthead__menu-item persist tail">
-            <a role="button"><i id="theme-icon" class="fa-solid fa-sun" aria-hidden="true" title="toggle theme"></i></a>
+            <a role="button" aria-labelledby="theme-icon"><i id="theme-icon" class="fa-solid fa-sun" aria-hidden="true" title="toggle theme"></i></a>
           </li>
         </ul>
         <ul class="hidden-links hidden"></ul>