Hints for rssguard in main

Warnings

• asv-tag-duplicated
  :31 - content_rating
  This tag must only appear once in this context. Having multiple tags of this kind is not valid.
• translations-not-found
  Unable to add languages information, even though a translation tag was present in the MetaInfo file. Please check that its value is set correctly, and all locale files are placed in the right directories (e.g. /usr/share/locale/*/LC_MESSAGES/ for Gettext .mo files).