Additional fixes to new notification docs

chrome/common/extensions/docs/templates/json/apps_sidenav.json

 [
   {
     "title": "Getting Started",
     "items": [
       {
         "title": "What Are Packaged Apps?",
         "fileName": "about_apps.html"
       },
       {
         "title": "Understand the Architecture",
@@ skipping 69 matching lines @@
                 "fileName": "gcm_server.html"
               },
               {
                 "title": "Terms of Service",
                 "fileName": "gcm_tos.html"
               }
             ]
           },
           {
             "title": "Desktop Notifications",
-            "fileName": "notifications.html"
+            "fileName": "desktop_notifications.html"
           }
         ]
       },
       {
         "title": "Advanced Technologies",
         "toggleable": true,
         "items": [
           {
             "title": "Network Communications",
             "fileName": "app_network.html"
@@ skipping 60 matching lines @@
   },
   {
     "title": "Samples",
     "fileName": "samples.html"
   },
   {
     "title": "Known Issues",
     "fileName": "app_known_issues.html"
   }
 ]