update Fest banner for slides coming soon (#2688)

* update Fest banner for slides coming soon

* Apply suggestions from code review

Co-authored-by: Don Naro <[email protected]>

---------

Co-authored-by: Don Naro <[email protected]>

Author: samccann

docs/docsite/.templates/banner.html

@@ -19,8 +19,8 @@
 
       var extra_banner =
       '<div id="latest_extra_banner_id" class="admonition important">' +
-        '<p style="font-size: 1.5rem;padding-bottom: 1.2rem;text-align: center;">' +
-        'Join AnsibleFest at <a href="https://www.redhat.com/en/summit?sc_cid=RHCTG1250000442936">Red Hat Summit</a>!' +
+        '<p style="padding-bottom: 1.2rem;text-align: center;">' +
+        'Slides for those who attended AnsibleFest at <a href="https://www.redhat.com/en/summit?sc_cid=RHCTG1250000442936">Red Hat Summit</a> will be available soon.' +
         '</p>' +
       '</div>';