docs: fix some LaTeX warnings

Fixes:

• Missing character: There is no (U+2006) in font LatinModernRoman:mode=node; script=latn;language=dflt;+tlig;! (fixed in Markdown, U+2006 it is basically just a short space)
• Class scrbook Warning: \float@addtolists detected! (fixed by addding scrhack package at the end)
• KOMA suggesting to add bookmark package
• LaTeX Font Warning: Font shape TU/LatinModernMono(0)/b/n' undefined(fixed by usingLatin Modern Mono Light`, looks much better overall IMHO)

Except for hbox/vbox warnings, we have a clean LaTeX build 🎉