fix lyrics search

[iiKurt]

Lyrics search sometimes returns a spotify track listing item, instead of the actual song

Example input: genius.search_song("a$ap forever (feat. moby)", "a$ap rocky")

Lyrics ouput: a list of tracks from "New Music Friday 04/06/18 by Spotify"

These changes fix this issue by finding the correct hit in the search results, ignoring hits with index = "lyric", instead with index = "song"