userMenu: Add translation comments

Seems like "console" vs. "remote" in the "other users" dialog  confuses some
translators so add a comments to clarify their meaning.

https://bugzilla.gnome.org/show_bug.cgi?id=695601

js/ui/userMenu.js

@@ -917,8 +917,10 @@ const UserMenuButton = new Lang.Class({
                            session.user.get_real_name() : session.username;
 
             if (session.info.remote)
+                /* Translators: Remote here refers to a remote session, like a ssh login */
                 userLabelText = _("%s (remote)").format(userName);
             else if (session.info.type == "tty")
+                /* Translators: Console here refers to a tty like a VT console */
                 userLabelText = _("%s (console)").format(userName);
             else
                 userLabelText = userName;