Remarks are not correct for .NET Core

[mairaw]

Original GitHub issue MicrosoftDocs/feedback#1636 from @RobSiklos

Link to article:
https://docs.microsoft.com/en-us/dotnet/api/system.security.cryptography.x509certificates.x509certificate2.privatekey?view=netcore-3.0#remarks

Problem:
The article says that the property "returns either an RSACryptoServiceProvider or a DSACryptoServiceProvider object". However, for .NET Core, this is not true.