Warning banner should only show on `/devel/` docs, not on pages with 'devel' in their titles (#70849) (#71076)

* banner should not be placed on pages with 'devel' in their titles

* Update docs/docsite/_themes/sphinx_rtd_theme/ansible_banner.html

* Only match paths at the beginning

Co-authored-by: Alicia Cozine <acozine@users.noreply.github.com>
Co-authored-by: Sviatoslav Sydorenko <webknjaz@redhat.com>
(cherry picked from commit 8313cc8fb1)

docs/docsite/_themes/sphinx_rtd_theme/ansible_banner.html

@@ -1,5 +1,8 @@
 <!--- Based on sphinx versionwarning extension. Extension currently only works on READTHEDOCS -->
   <script>
+    startsWith = function(str, needle) {
+      return str.slice(0, needle.length) == needle
+    }
     // Create a banner if we're not on the official docs site
     if (location.host == "docs.testing.ansible.com") {
       document.write('<div id="testing_banner_id" class="admonition important">');
@@ -10,15 +13,15 @@
       element.appendChild(para);
       document.write('</div>');
     }
-
+    {% if (not READTHEDOCS) and (available_versions is defined) %}
       // Create a banner if we're not the latest version
-    current_url = window.location.href;
-    if ((current_url.search("latest") > -1) || (current_url.search("/{{ latest_version }}/") > -1)) {
+      current_url_path = window.location.pathname;
+      if (startsWith(current_url_path, "/ansible/latest/") || startsWith(current_url_path, "/ansible/{{ latest_version }}/")) {
        // no banner for latest release
-    } else if (current_url.search("devel") > -1) {
+      } else if (startsWith(current_url_path, "/ansible/devel/")) {
         document.write('<div id="banner_id" class="admonition caution">');
         para = document.createElement('p');
-      banner_text=document.createTextNode("You are reading the *devel* version of the Ansible documentation - most module documentation is currently missing as the modules have moved to collections. Until docs catches up to this change, use the version selection to the left if you want module documentation or the latest stable release version. The *devel* version is not guaranteed stable.");
+        banner_text=document.createTextNode("You are reading the *devel* version of the Ansible documentation - this version is not guaranteed stable. Use the version selection to the left if you want the latest stable released version.");
         para.appendChild(banner_text);
         element = document.getElementById('banner_id');
         element.appendChild(para);
@@ -32,4 +35,5 @@
         element.appendChild(para);
         document.write('</div>');
       }
+    {% endif %}
   </script>