Removing duplicate tip block (dotnet#3383)

that gives guidelines for installation

Author: jigargandhi

docs/standard/parallel-programming/walkthrough-using-dataflow-in-a-windows-forms-application.md

@@ -28,9 +28,7 @@ This document demonstrates how to create a network of dataflow blocks that perfo
 
 > [!TIP]
 >  The TPL Dataflow Library (<xref:System.Threading.Tasks.Dataflow?displayProperty=nameWithType> namespace) is not distributed with the [!INCLUDE[net_v45](../../../includes/net-v45-md.md)]. To install the <xref:System.Threading.Tasks.Dataflow> namespace, open your project in [!INCLUDE[vs_dev11_long](../../../includes/vs-dev11-long-md.md)], choose **Manage NuGet Packages** from the Project menu, and search online for the `Microsoft.Tpl.Dataflow` package.  
-  
-> [!TIP]
->  The TPL Dataflow Library (<xref:System.Threading.Tasks.Dataflow?displayProperty=nameWithType> namespace) is not distributed with the [!INCLUDE[net_v45](../../../includes/net-v45-md.md)]. To install the <xref:System.Threading.Tasks.Dataflow> namespace, open your project in [!INCLUDE[vs_dev11_long](../../../includes/vs-dev11-long-md.md)], choose **Manage NuGet Packages** from the Project menu, and search online for the `Microsoft.Tpl.Dataflow` package.  
+ 
 
 ## Sections  
  This walkthrough contains the following sections: