Upgrade the manual to docbook 5.0

To upgrade the manual:
  sudo dnf install -y docbook5-schemas
  xsltproc --output index-new.docbook /usr/share/xml/docbook5/stylesheet/upgrade/db4-upgrade.xsl index.docbook
  xsltproc --output legal-new.xml /usr/share/xml/docbook5/stylesheet/upgrade/db4-upgrade.xsl legal.xml

To validate the manual:
  xmllint --noout --relaxng /usr/share/xml/docbook5/schema/rng/5.0/docbook.rng help/C/index.docbook
  jing /usr/share/xml/docbook5/schema/rng/5.0/docbook.rng help/C/index.docbook
  yelp-check validate help/C/index.docbook

To view the manual:
  yelp file:///full_path/index.docbook

Note: docbook5-schemas should be installed in your system in order to view the manual (DEPENDENCY)

Author: rbuj