show web-push subscription info on demand, and refine docs

src/App.vue

@@ -402,7 +402,10 @@ export default class App extends Vue {
   private requestNotificationPermission(): Promise<NotificationPermission> {
     return Notification.requestPermission().then((permission) => {
       if (permission !== "granted") {
-        alert("We need notification permission to provide certain features.");
+        alert(
+          "Allow this app permission to make notifications for personal reminders." +
+            " You can adjust them at any time in your settings.",
+        );
         throw new Error("We weren't granted permission.");
       }
       return permission;