Update Remove-AzureRmVirtualNetworkPeering.md

Fixed the header in the file, Added a description and Synopsis

Author: markjbrown

src/ResourceManager/Network/Commands.Network/help/Remove-AzureRmVirtualNetworkPeering.md

@@ -1,4 +1,4 @@
----
+---
 external help file: Microsoft.Azure.Commands.Network.dll-Help.xml
 Module Name: AzureRM.Network
 ms.assetid: 1CE08F0F-A59E-46AC-B470-F1DCCD46513E
@@ -9,6 +9,7 @@ schema: 2.0.0
 # Remove-AzureRmVirtualNetworkPeering
 
 ## SYNOPSIS
+Removes a virtual network peering.
 
 ## SYNTAX
 
@@ -19,6 +20,7 @@ Remove-AzureRmVirtualNetworkPeering -VirtualNetworkName <String> -Name <String>
 ```
 
 ## DESCRIPTION
+Removes a virtual network peering.
 
 ## EXAMPLES