Add article for non-conformance of the Microsoft (roslyn) compiler

We should add and maintain an article that describes the ways in which the Microsoft compiler doesn't conform to the standard.

See https://github.com/dotnet/csharpstandard/pull/601/files#r1171826877 for one example.

This information may already exist in the [dotnet/roslyn](https://github.com/dotnet/roslyn) repo. In which case, we should publish it at this location.

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#### Document Details

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* ID: 85c9d0ef-c6b0-87f2-746d-6940b1377a54
* Version Independent ID: 575e8c7c-a170-a9d0-ee59-c42451cd1ac9
* Content: [Table of contents - C# language specification](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/language-specification/readme)
* Content Source: [standard/README.md](https://github.com/dotnet/csharpstandard/blob/draft-v7/standard/README.md)
* Product: **dotnet-csharp**
* Technology: **csharp-spec**
* GitHub Login: @dotnet-bot
* Microsoft Alias: **wiwagn**