WinForms Accessibility Documentation

[M-Lipin]

WinForms Accessibility Documentation needs to be added

• Need to add the description of new accessibility features, behavior changes and improvements added to .NET Core 3.0 WinForms.
• At this moment there is a documentation about WinForms Accessibility features compatibility in https://github.com/microsoft/dotnet/tree/master/Documentation/compatibility documents regarding changes in .NET Framework.

WinForms Accessibility Documentation for .NET Core 3.0

• There is a number of changes in WinForms Accessibility which are not documented yet.
• Accessibility changes in latest version of .NET Framework are documented but there are differences between .NET Framework 4.8 WinForms and .NET Core WinForms in this area.
• To describe the changes and compatibility between .NET Framework WinForms accessibility and .NET Core WinForms accessibility we need to add corresponding document.