Minor update to incoming calls notification demo (#93)

* Update incoming calls demo to show capitalized icon

* Update incoming calls readme

Author: liminzhu

incoming-call-notifications/README.md

@@ -2,7 +2,7 @@
 
 ➡️ **[Open the demo](https://microsoftedge.github.io/Demos/incoming-call-notifications/)** ⬅️
 
-The Notifications demo webpage shows how to use incoming call notifications.
+The Notifications demo webpage shows how to use incoming call notifications. Note you need to install the demo website PWA to experience the full feature with color treatment, etc. 
 <!--
 For instructions, see []().
 todo: not found in Docs repo: incoming-call-notifications

incoming-call-notifications/index.html

@@ -108,8 +108,8 @@ <h2>Log</h2>
           icon: "./call.png",
           scenario: "incoming-call",
           actions: [
-            { action: "accept-audio-call", title: "audio" },
-            { action: "accept-video-call", title: "video" }
+            { action: "accept-audio-call", title: "Audio" },
+            { action: "accept-video-call", title: "Video" }
           ]
         }).then(() => {
           log("showNotification() succeeded");
@@ -136,4 +136,4 @@ <h2>Log</h2>
   </script>
 </body>
 
-</html>
+</html>