Fix core banner (#2706) (#2710)

* add core 2.19 banner to core docs

* remove Ansible 12 mention

(cherry picked from commit f1f5220)

Co-authored-by: Sandra McCann <[email protected]>

Author: patchback[bot]

docs/docsite/.templates/banner.html

@@ -38,6 +38,8 @@
       var msg = '<p>';
       if (startsWith(current_url_path, "/ansible-core/")) {
         msg += 'You are reading documentation for Ansible Core, which contains no plugins except for those in ansible.builtin. For documentation of the Ansible package, go to <a href="/ansible/latest">the latest documentation</a>.';
+        /* temp - add extra warning about core-2.19. This should move to latest at release time */
+        msg += '<br><p><strong>Important:</strong> The ansible-core 2.19 release has made <b>significant templating changes that might require you to update playbooks and roles</b>. The templating changes enable reporting of numerous problematic behaviors that went undetected in previous releases, with wide-ranging positive effects on security, performance, and user experience. You should validate your content to ensure compatibility with these templating changes before upgrading to ansible-core 2.19. See the <a href="https://docs.ansible.com/ansible/devel/porting_guides/porting_guide_12.html">porting guide</a> to understand where you may need to update your playbooks and roles.';
       } else if (startsWithOneOf(current_url_path, ["/ansible/latest/", "/ansible/{{ latest_version }}/"])) {
         /* temp extra banner to advertise something */
         banner += extra_banner;