[cleanup] Updated documents to the new xar format.

(cherry picked from commit 721d9e0f6fcaee3b6c1411568f384ce91a216c08)
XWIKI-11032: The "Reply" icon is not shown for an annotation
- Using custom annotations css for the reply button instead of reusing from comments.css

(cherry picked from commit cbceeff42039e009f6234b4e0a96337637f61761)