swift

cc75d5e0 - Allow `@preconcurrency` to suppress an implied Sendable conformance

Allow `@preconcurrency` to suppress an implied Sendable conformance When a retroactive conformance to a protocol that inherits from `Sendable` introduces an implicit `Sendable` conformance, allow `@preconcurrency` to suppress the diagnostic about the `Sendable` conformance being introduced outside of the original source file. Fixes rdar://125080066.