swift

d1737b9c - [Swiftify] Add MutableSpan support for std::span, and disable it (#80315)

[Swiftify] Add MutableSpan support for std::span, and disable it (#80315) __counted_by already had MutableSpan support, so add it for std::span for parity. But since MutableSpan hasn't landed in the standard library yet, disable emitting it to prevent compilation errors in expansions. rdar://147882736