Hints for screenkey in main

Hints

• asv-description-first-para-too-short
  <code>org.thregr.screenkey.metainfo.xml:13</code> - <em>A screencast tool to display your keys.</em><br/>The first `description/p` paragraph of this component might be too short (&lt; 80 characters). Please consider starting with a longer paragraph to improve how the description looks like in software centers and to provide more detailed information on this component immediately in the first paragraph.
• asv-content-rating-missing
  <code>org.thregr.screenkey.metainfo.xml</code> - <em></em><br/>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/
• asv-developer-info-missing
  <code>org.thregr.screenkey.metainfo.xml</code> - <em></em><br/>This component contains no `developer` element with information about its author.