Add a section to the Picard documentation to explain the symbols used for the release and track lines displayed in the right hand pane when tagging. For example, on the track lines the meaning of the musical note symbol and the different colour boxes (varing from red to green). These are described well in the [Loading releases from musicbrainz.org into Picard](https://community.metabrainz.org/t/loading-releases-from-musicbrainz-org-into-picard/4867) thread in the community discussion forum.

See the Clarification on Picard usage thread in the community discussion forum for additional information.