MFde: Update the German Documentation set.

Fix my "off by one" error in the commit marker in the overview chapter of
the german FDP Primer. This silences the "REVISION ERROR" messages from
mfen.sh along with it.

This commit brings several handbook chapters in sync with the latest
revision on FreeBSD.org.

doc/de_DE.ISO8859-1/articles/contributing/article.sgml 1.508 -> 1.511
doc/de_DE.ISO8859-1/books/fdp-primer/overview/chapter.sgml 1.25 -> 1.24
doc/de_DE.ISO8859-1/books/handbook/kernelconfig/chapter.sgml 1.180 -> 1.184
doc/de_DE.ISO8859-1/books/handbook/l10n/chapter.sgml 1.124 -> 1.128
doc/de_DE.ISO8859-1/books/handbook/mail/chapter.sgml 1.136 -> 1.138
doc/de_DE.ISO8859-1/books/handbook/multimedia/chapter.sgml 1.128 -> 1.131
doc/de_DE.ISO8859-1/books/handbook/vinum/chapter.sgml 1.44 -> 1.46

Obtained from: The FreeBSD German Documentation Project
Approved by: jkois (mentor)