MFde: Update the German Documentation set

doc/de_DE.ISO8859-1/books/fdp-primer/sgml-markup/chapter.sgml 1.78 -> 1.79
doc/de_DE.ISO8859-1/books/handbook/advanced-networking/chapter.sgml 1.425 -> 1.426 + fixes/updates [X]
doc/de_DE.ISO8859-1/books/handbook/network-servers/chapter.sgml Fixes only

Obtained from: The FreeBSD German Documentation Project

• Contributed by:

Typo findings/Fixes: Daniel Seuffert, Bastian Therres
Translation update: Frank Boerner