[docs] LibraryEvolution: Discuss nominal members explicitly.
[docs] LibraryEvolution: Discuss nominal members explicitly.

I realized "members are mostly the same as their top-level equivalents" is worth
calling out explicitly, especially for subscripts and initializers without top-level
equivalents. There's still a hole here for members of protocol extensions, which can
have pretty drastic effects on conforming types.

khizkhiz/swift,khizkhiz/swift,khizkhiz/swift,khizkhiz/swift,khizkhiz/swift,khizkhiz/swift,khizkhiz/swift