TOC is missing when displaying a particular page revision

[annda]

Issue Description

When you open a particular page revision from page history, the Table of Contents is not rendered.

This is caused by a check for $REV in DokuWiki core
https://github.com/dokuwiki/dokuwiki/blob/bcedcbabaeed53ef96a52034226c5be6d16f07d3/inc/template.php#L153

Because SprintDoc renders the TOC separately from the main page content, it needs to make sure the TOC gets created, e.g. by populating the $TOC global variable.