Invoking SetCookie instead of Add

[slobo80]

The example incorrectly is invoking Add( method instead of SetCookie

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[dnfclas]

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[rpetrusha]

Thanks for pointing to this inconsistency, @slobo80. As your PR #1917 notes, though, HttpResponse.SetCookie is for internal use only. Given that, we don't want to provide an example that calls the internal-only member.
Rather than modifying the code, would you mind revising the comment that precedes the code? It can read something like, "Because the HttpResponse.SetCookie method is intended for internal use only, you should not call it in your code. Instead, you can all the HttpResponse.Cookies.Add method, as the following example shows." Thanks.

[rpetrusha]

Changes requested in previous comment.

[guardrex]

VB code shows SetCookie ...

https://github.com/dotnet/docs/blob/master/samples/snippets/visualbasic/VS_Snippets_WebNet/Classic%20HttpResponse.SetCookie%20Example/VB/source.vb

[rpetrusha]

Sorry, @slobo80, I looked at the C# code but not the VB code. Would you mind changing the VB code as well to call Add instead of SetCookie? If that's too much trouble, let us know, and we can close this PR and open one ourselves.

[slobo80]

Submitted a new PR for the VB code.