These variables are renamed
* 'html-bodycontent' => 'html-body-content'
* 'html-undelete' => 'html-undelete-link'
* 'html-sitenotice' => 'html-site-notices'
* 'html-catlinks' => 'html-categories'
* 'html-aftercontent' => 'html-after-content'
* 'html-userlanguageattributes' => 'html-user-language-attributes'
Others
* 'html-printfooter' is now subsumed into 'html-body-content'
* Factored out the bottom elements into a standalone method to
properly separate roles and make presentation a bit more clear:
=> headElement() -> body composition -> tailElement().
Bug: T257630
Change-Id: Ibac9729eaa96a38bc730a0132b102a894f6a172d
8acef095b9