…mentation_103

… of virtual static members. (dotnet#60965)

https://github.com/dotnet/csharplang/blob/main/proposals/static-abstracts-in-interfaces.md

…otnet#61133)

…otnet#61134)

https://github.com/dotnet/csharplang/blob/main/proposals/static-abstracts-in-interfaces.md

Test plan: dotnet#60968

Tests in DefaultInterfaceImplementationTests.cs are adjusted only for methods. Tests for other members will be adjusted separately.

…otnet#61200)

…et#61201)

…otnet#61244)

https://github.com/dotnet/csharplang/blob/main/proposals/static-abstracts-in-interfaces.md

…otnet#61253)

…mentation' into DefaultInterfaceImplementation_115