a_dndtoggle: add comments to explain settings a bit better

apps/a_dndtoggle/README.md

@@ -1,6 +1,9 @@
 # a_dndtoggle - Toggle Quiet Mode of the watch
 
 When Quiet mode is off, just start this app to set quiet mode. Start it again to turn off quiet mode.
+
+Use the app settings to choose which quiet mode you prefer ("Alarms" or "Silent"). Default is "Silent".
+
 Work in progress.
 
 #ToDo

apps/a_dndtoggle/settings.js

@@ -8,13 +8,15 @@
     }
 
     function buildMainMenu(){
+      // 0-Noisy is only a placeholder so that the other values map to the Bangle quiet mode options
       const modes = [/*LANG*/"Noisy",/*LANG*/"Alarms",/*LANG*/"Silent"];
       let mainmenu = {
         '': { 'title': 'A_DND Toggle' },
         '< Back': back,
         /*LANG*/"Quiet Mode": {
           value: settings.mode || 2,
-          min: 1, max: modes.length - 1,
+          min: 1, // don't allow choosing 0-Noisy
+          max: modes.length - 1,
           format: v => modes[v],
           onchange: v => {
             settings.mode = v;