SE-0258: Property Wrappers (second review)

[Douglas_Gregor]

@NobodyNada

I agree that Codable is an important use case for property wrappers. Last I checked (Xcode 11 beta 1), the default automatically synthesized coding key for a wrapped property is $foo . I think this should be changed to just foo before the release so that we can write wrappers to provide custom encoding utilities.

This has already been fixed in the compiler to align with the proposal under review, but the changes didn't make it into Xcode 11 beta 1 or 2.

Doug