macosx: Remove playlist view controller todo comment now that it has been addressed

Signed-off-by: Claudio Cambra <developer@claudiocambra.com>

modules/gui/macosx/library/playlist-library/VLCLibraryPlaylistViewController.m

@@ -223,9 +223,6 @@
     return self.dataSource;
 }
 
-// TODO: This is duplicated almost verbatim across all the library view
-// controllers. Ideally we should have the placeholder view handle this
-// itself, or move this into a common superclass
 - (void)presentPlaceholderPlaylistLibraryView
 {
     const vlc_ml_playlist_type_t playlistType = self.dataSource.playlistType;