call format hooks when generating page previews

call format hooks when generating page previews

* toc: Revert change in 2.45 that made it run at sanitize time. This breaks
  use of toc in a sidebar.
* Call format hooks when generating page previews, thus fixing toc display
  there, as well as fixing inlins to again display in page previews, since
  it's started using format hooks. This also allows several other things,
  like embed, that use format hooks, to work during page preview time.
* Format hooks should not rely on getting an entire html document, as they
  will only get the body during page preview.
* toggle: Deal with preview mode when adding javascript.