DOC add link for Discussions in the footer (scikit-learn#31704)

Author: reshamas

doc/templates/index.html

@@ -222,7 +222,7 @@ <h4 class="sk-landing-call-header">Community</h4>
         <ul class="sk-landing-call-list list-unstyled">
           <li><strong>About us:</strong> See <a href="about.html#the-people-behind-scikit-learn">people</a> and <a href="{{ contributing_link }}" {{ contributing_attrs }}>contributing</a></li>
           <li><strong>More Machine Learning:</strong> Find <a href="related_projects.html">related projects</a></li>
-          <li><strong>Questions?</strong> See <a href="faq.html">FAQ</a>, <a href="support.html">support</a>, and <a href="https://stackoverflow.com/questions/tagged/scikit-learn">stackoverflow</a></li>
+          <li><strong>Questions?</strong> See <a href="faq.html">FAQ</a>, <a href="support.html">Support</a>, <a href="https://github.com/scikit-learn/scikit-learn/discussions">Discussions</a>, and <a href="https://stackoverflow.com/questions/tagged/scikit-learn">Stack Overflow</a></li>
           <li><strong>Subscribe to the</strong> <a href="https://mail.python.org/mailman/listinfo/scikit-learn">mailing list</a></li>
           <li><strong>Blog:</strong> <a href="https://blog.scikit-learn.org">blog.scikit-learn.org</a></li>
           <li><strong>Logos & Branding:</strong> <a href="https://github.com/scikit-learn/scikit-learn/tree/main/doc/logos">logos and branding</a></li>