Documentation for CodePagesEncodingProvider is out of date

[svick]

This page has several issues:

1. It claims CodePagesEncodingProvider is not available for .Net Core 2.1, which is not true. (In fact, it's a NuGet package, so AFAIK it's not part of any .Net TFM, but works in any .Net Standard 1.3+ TFM, if installed. But I think that's a larger issue that's out of scope here.)
2. It claims it's only relevant for .Net Native. That's not true, CodePagesEncodingProvider is also required for some code pages on regular .Net Core.
3. It says that you should reference the System.Text.Encoding.CodePages.dll assembly. That might work on UWP (not sure), but a more general approach is to reference the System.Text.Encoding.CodePages package from NuGet.

This issue was inspired by https://github.com/dotnet/docs/issues/6931.

---

Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: a5c26a9c-9378-f153-0e10-2d893d8ea178
• Version Independent ID: 5a122d68-cd0b-abe8-fd6c-258d44c816a2
• Content: CodePagesEncodingProvider Class (System.Text)
• Content Source: xml/System.Text/CodePagesEncodingProvider.xml
• Product: dotnet-api
• GitHub Login: @rpetrusha
• Microsoft Alias: ronpet