TBR playground: change error message to say 'Coming soon'

Change-Id: I7055b5681643e254ad6604ab780fa56cef4975f0
diff --git a/client/browser/index.js b/client/browser/index.js
index 7476ad5..18e3b72 100644
--- a/client/browser/index.js
+++ b/client/browser/index.js
@@ -54,9 +54,9 @@
     api.bundles(function(err, list) {
       if (err) {
         state.error.set(error({
-          title: 'API Error',
-          body: 'There was problem retrieving the list of examples. ' +
-            'Please try again later.',
+          title: 'Coming soon',
+          body: 'A web-based code editing application for experimenting ' +
+            'with Vanadium.',
           error: err
         }));