Wrong or missing F# examples for `MarshalByRefObject`

When browsing the documentation for `MarshalByRefObject` and selecting F# as a language, the code examples appear in C++. For C#, VB.NET and C++ the examples show in the correct language.

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#### Document Details

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* ID: 060a3bb9-8fe6-a034-5413-8827ae63fb75
* Version Independent ID: c2f0e48f-a1d6-5c04-ec17-edf17d9d69ba
* Content: [MarshalByRefObject Class (System)](https://docs.microsoft.com/en-us/dotnet/api/system.marshalbyrefobject?redirectedfrom=MSDN&view=netframework-4.7.2)
* Content Source: [xml/System/MarshalByRefObject.xml](https://github.com/dotnet/dotnet-api-docs/blob/master/xml/System/MarshalByRefObject.xml)
* Product: **dotnet-api**
* GitHub Login: @rpetrusha
* Microsoft Alias: **ronpet**

Start with xml/System/MarshalByRefObject.xml, the content source linked in the issue, and compare its language-specific examples with the rendered MarshalByRefObject documentation page. Verify how the F# language selection maps to the examples; done means F# shows F# examples rather than C++ while the C#, VB.NET, and C++ examples remain correct.

Scritto dal modello di indicizzazione a partire dal testo della issue.