Fix page-description attribute not rendering as meta description tag (#10567)

Antora strips the 'page-' prefix when building page.attributes, so
:page-description: is stored as page.attributes.description, not
page.description (which comes from the bare :description: attribute).
The template was only checking page.description, so the meta description
tag was never emitted. Updated to check both.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: rosieyohannan

ui/src/partials/head-info.hbs

@@ -11,7 +11,7 @@
     <link rel="next" href="{{{relativize ./url}}}">
     {{/with}}
     {{/unless}}
-    {{#with page.description}}
+    {{#with (or page.description page.attributes.description)}}
     <meta name="description" content="{{{detag this}}}">
     {{/with}}
     {{#with page.keywords}}