ca861d8ff9
As the user menu no longer really shows anything about the user, and just power menu and settings, it's not really deserving of the "user menu" name, so rename it to the ever-blandly-named "system menu". This is a part of the new system status design, see https://wiki.gnome.org/GnomeShell/Design/Guidelines/SystemStatus/ for design details. https://bugzilla.gnome.org/show_bug.cgi?id=704368