Unlisted chords

Example: 'A Horse With No Name' by America. A 2 chord song, an Em and a D6Add9/F#, however, there is no way to annotate the D6Add9/F#. It would be nice if when you edited a song to have a comments section. In the comments section you could explain how the D6 on the song is actually a D6Add9/F#. Also, you could diagram the chord.