Update Mardown files

content/fit-standards/string_latin/string_latin.md

content/fit-standards/xbau/xbau.md

content/fit-standards/xbreitband/xbreitband.md

content/fit-standards/xdomea/xdomea.md

content/fit-standards/xeinkauf/xeinkauf.md

content/fit-standards/xfall/xfall.md

content/fit-standards/xplanung/xplanung.md

content/fit-standards/xprozess/xprozess.md

content/fit-standards/xrechnung/xrechnung.md

content/fit-standards/xschule/xschule.md

content/fit-standards/xta/xta.md

content/fit-standards/xzufi/xzufi.md

views/fit-standards/NavigationHeader.tsx