Bug 474964

I want to add a template with headed code and with syntax highlighting.
Here is a page: https://community.kde.org/Template:Hc-hl

There should be applied a custom style for the element generated by syntaxhighlight tag. More precisely, a pre tag under the div. See [here](https://phabricator.wikimedia.org/T347527) for details.

It requires the wiki instance to have [TemplateStyles](https://www.mediawiki.org/wiki/Help:TemplateStyles) extension. After it is installed, it will be possible to change the [page's content model](https://community.kde.org/index.php?title=Template:Hc-hl/styles.css&action=info) to "Sanitized CSS".

STEPS TO REPRODUCE
1. Visit https://community.kde.org/Special:Version
2. Search for TemplateStyles extension

OBSERVED RESULT
There is no such extension

EXPECTED RESULT
There should be that extension.

ADDITIONAL INFORMATION
See the example page content model: https://www.mediawiki.org/w/index.php?title=Template:Stylish/styles.css&action=info
See the MediaWiki has TemplateStyles extension: https://www.mediawiki.org/wiki/Special:Version