Remove reference to crystal-ann.com (#908)

The site has been shut down
crystal-community/crystal-ann#76

Author: straight-shoota

_pages/community.html

@@ -106,14 +106,6 @@ <h3>News</h3>
         </a>
         <p>Get news and engage in discussions on Mastodon and Twitter.<br> Be sure to mention us in your toots and tweets!</p>
       </div>
-
-      <div class="link-item">
-        <a class="link-item__main" href="https://crystal-ann.com">
-          {%- include icons/announce.svg %}
-          Crystal [ANN]
-        </a>
-        <p>Announcements of new projects, blog posts, version updates or any other Crystal work.</p>
-      </div>
     </div>
   </div>
 </section>