Update docstring for parse_library()

The docstring of parse_library still mentions the library_stats
dictionary, which had already been removed.

spotifyvis/utils.py

@@ -15,7 +15,7 @@ import json
 
 
 def parse_library(headers, tracks, user):
-    """Scans user's library for certain number of tracks to update library_stats with.
+    """Scans user's library for certain number of tracks and store the information in a database
 
     :headers: For API call.
     :tracks: Number of tracks to get from user's library.