move nwburg template back to pandoc instead of highlightjs linting

[MatthiasPopp]

After talking to @marcerich we will adopt the Pandoc Syntax Highlighting test deck for code highlighting with the nwburg template. Thus we do not need the buggy code section. I need the modifications to the template so that others in Würzburg can improve on the styling. Would you please merge them? Best, Matthias

[monofon]

Done.