Hints for surfer in main

Hints

• asv-summary-has-dot-suffix
  com.gitlab.surferproject.surfer.metainfo.xml:10 - A waveform viewer with a focus on a snappy usable interface, and extensibility.
  The component summary should not end with a dot (`.`).
• asv-content-rating-missing
  com.gitlab.surferproject.surfer.metainfo.xml -
  This component has no `content_rating` tag to provide age rating information. You can generate the tag data online by answering a few questions at https://hughsie.github.io/oars/