Updating metadata_to_use docs to be more consistent with tagtypes command.

doc/mpd.conf.5

@@ -234,7 +234,7 @@ This specifies whether relative or absolute paths for song filenames are used
 when saving playlists.  The default is "no".
 .TP
 .B metadata_to_use <tags>
-This specifies the song metadata that will be scanned and made available to
+This specifies the tag types that will be scanned for and made available to
 clients.  Note that you must recreate (not update) your database for changes to
 this parameter to take effect.  Possible values are artist, album, title,
 track, name, genre, date, composer, performer, comment, and disc.  Multiple

doc/mpdconf.example

@@ -259,7 +259,8 @@ error_file                      "~/.mpd/mpd.error"
 #
 #save_absolute_paths_in_playlists "no"
 #
-# The metadata types MPD will recognize.
+# A list of tag types that MPD will scan for and make available
+# to clients.
 #
 #metadata_to_use                  "artist,album,title,track,name,genre,date,composer,performer,disc"
 #