fix: Docs banner resolves relative URL

This patch is a small addendum to the previous doc-related change.
The relative URL is now correctly resolved regardless of the root
of the site.

docs/www/themes/material/main.html

@@ -6,10 +6,10 @@
   <!-- Add announcement here, including arbitrary HTML -->
   ✨ Please check out
   <em>
-    <a href="./concepts/images/vm-image/#image-names">Image Names</a>
+    <a href="{{ 'concepts/images/vm-image/#image-names' | url }}">Image Names</a>
   </em> and
   <em>
-    <a href="./concepts/images/vm-image/#name-resolution">Name Resolution</a>
+    <a href="{{ 'concepts/images/vm-image/#name-resolution' | url }}">Name Resolution</a>
   </em>
   to learn about changes to <code>VirtualMachineImage</code> and
   <code>ClusterVirtualMachineImage</code> resources in vSphere 8.0U2+ ✨