Update working-groups.html

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Stephen R. Aylward <stephen@aylward.org>

Author: aylward

working-groups.html

@@ -532,7 +532,7 @@ <h4 class="uppercase text-sm font-medium text-gray-600 mb-4">GROUP LEADS</h4>
                     </ul>
                   </div>
                   <div>
-                    <a href="wg_ultrasound.html" class="px-6 py-2.5 rounded-lg bg-white text-brand-primary border-2 border-brand-primary hover:bg-brand-light transition-colors inline-flex items-center gap-2 group">
+                    <a href="wg_ultasound.html" class="px-6 py-2.5 rounded-lg bg-white text-brand-primary border-2 border-brand-primary hover:bg-brand-light transition-colors inline-flex items-center gap-2 group">
                         <span>Learn More</span>
                         <svg class="w-4 h-4 transition-transform group-hover:translate-x-1" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                             <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M13 7l5 5m0 0l-5 5m5-5H6"></path>