Merge pull request plone#1504 from plone/404-add-versions

Change wording and include reference to previous versions of Plone do…

Author: fredvd

docs/_templates/404.html

@@ -7,7 +7,19 @@
 {% block body %}
 <div>
     <h1>Page not found</h1>
-    <p>Unfortunately we couldn't find the content you were looking for. Use this site's <a href="/search.html">search</a> to find what you seek.</p>
+    <p>We could not find the page you requested in Plone 6 documentation.</p>
+    <p>You can <a href="/search.html">search</a> Plone 6 documentation.</p>
+    <p>Previous versions of Plone documentation:</p>
+    <ul>
+        <li><a href="https://5.docs.plone.org/">Plone 5</a></li>
+        <li><a href="https://4.docs.plone.org/">Plone 4</a></li>
+        <li><a href="https://3.docs.plone.org/">Plone 3</a></li>
+    </ul>
+    <h2>Why is this happening?</h2>
+    <p>
+        The Plone Documentation team has restructured documentation to redirect visitors to the most current and accurate information, archive previous versions, and identify outdated pages.
+        If you would like to report an issue or request a redirect be set up, you can <a href="https://github.com/plone/documentation/issues/new?assignees=&labels=&projects=&template=new-issue-form.yml" rel="external">create a new issue in the GitHub issue tracker</a>.
+    </p>
 </div>
 
 <style>

docs/classic-ui/images.md

@@ -262,7 +262,7 @@ To access image scales, which are normally not accessible to the current user, o
 ## Responsive image support
 
 Plone supports the generation of picture tags with `srcset`s for image optimization.
-Additionally, you can define [media queries](https://developer.mozilla.org/en-US/docs/Web/CSS/Media_Queries/Using_media_queries) for [art direction](classic-ui-images-responsive-image-support-art-direction) and further optimization.
+Additionally, you can define [media queries](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_media_queries/Using_media_queries) for [art direction](classic-ui-images-responsive-image-support-art-direction) and further optimization.
 
 The configuration allows you to define different picture variants, such as `Large`, `Medium`, or `Small`.
 Users can choose from them in editors, such as TinyMCE, and developers can use them in templates.