Add "user.filter" to "Edit" menu

Right-clicking Privoxy's systray icon shows an "Edit" menu. The list of files to edit includes config.txt, default.action, default.filter and user.action. It does not include user.filter, however. Now that that file is scheduled to be enabled by default in the next version of Privoxy (https://sourceforge.net/tracker/?func=detail&atid=211118&aid=3001830&group_id=11118) , please add a "User Filters" item to the Edit menu so user.filter can be easily accessed. Thank you.