Add changelog for #6493 smartplaylist quiet option

Author: JOJ0

docs/changelog.rst

@@ -26,6 +26,11 @@ New features
   unknown playlist name is passed as an argument is now sorted alphabetically
   and printed space-delimited and POSIX shell-quoted when required. This makes
   it easier to copy and paste multiple playlists for further use in the shell.
+- :doc:`plugins/smartplaylist`: A ``--quiet`` flag is added to the ``splupdate``
+  command to suppress several log messages for each updated playlist and in
+  pretend mode only prints the playlist name and the number of tracks instead of
+  each track name. This can be useful when testing out new entries in the
+  configuration.
 
 Bug fixes
 ~~~~~~~~~