improve docs for tvos (#577)

Author: toto

_includes/ios/push-notifications.md

@@ -58,7 +58,7 @@ While it is possible to modify a `PFInstallation` just like you would a `PFObjec
 *   **`channels`**: An array of the channels to which a device is currently subscribed.
 *   **`badge`**: The current value of the icon badge for iOS/OS X apps. Changing this value on the `PFInstallation` will update the badge value on the app icon. Changes should be saved to the server so that they will be used for future badge-increment push notifications.
 *   **`installationId`**: Unique Id for the device used by Parse _(readonly)_.
-*   **`deviceType`**: The type of device, "ios", "osx", "android", "winrt", "winphone", "dotnet", or "embedded". On iOS and OS X devices, this field will be set to "ios" and "osx", respectively _(readonly)_.
+*   **`deviceType`**: The type of device, "ios", "tvos", "osx", "android", "winrt", "winphone", "dotnet", or "embedded". On iOS, tvOS and OS X devices, this field will be set to "ios", "tvos" and "osx", respectively _(readonly)_.
 *   **`deviceToken`**: The Apple generated token used for iOS/OS X devices. On Android devices, this is the token used by FCM to keep track of registration ID _(readonly)_.
 *   **`appName`**: The display name of the client application to which this installation belongs. In iOS/OS X, this value is obtained from `kCFBundleNameKey`. This value is synchronized every time a `PFInstallation` object is saved from the device _(readonly)_.
 *   **`appVersion`**: The version string of the client application to which this installation belongs. In iOS/OS X, this value is obtained from `kCFBundleVersionKey`. This value is synchronized every time a `PFInstallation` object is saved from the device _(readonly)_.

_includes/parse-server/push-notifications.md

@@ -121,11 +121,17 @@ push: {
       bundleId: '',  
       production: true // Prod
     }
+  ],
+  tvos: [
+    // ...
+  ],
+  osx: [
+    // ...
   ]
 }
 ```
 
-The configuration for macOS and tvOS works exactly as for iOS. Just add an additional configuration for each plattform. Please note the key for macOS is `osx`. If you need to support both the dev and prod certificates, you can do that for all Apple plattforms like described above.
+The configuration for macOS and tvOS works exactly as for iOS. Just add an additional configuration for each plattform under the appropriate key. Please note the key for macOS is `osx` and for tvOS is `tvos`. If you need to support both the dev and prod certificates, you can do that for all Apple plattforms like described above.
 
 ```js
 var server = new ParseServer({