v4.0.21
Code Quality: Ran code cleanup (#17307)
Code Quality: Improved the new Windows thumbnail API (#17071)
Code Quality: Generate a COM vtable call from [GeneratedVTableFunction] (#17570)
Code Quality: Introduced the new WindowsStorable (#17002)
Code Quality: Improved WindowsStorables (#17191)
Code Quality: Force PreserveSig to all COM methods generated by CsWin32 (#16121)