SendableKeyPath?

[hborla (Holly Borla)]

@Karl

There was some discussion about loosening this, and having sendable keypath literals produce KeyPath & Sendable, but AFAICT that never made it in to a proposal.

Lifting the unconditional Sendable restriction on key-path literals and instead inferring Sendable based on captures has been pitched at [Pitch] Inferring @Sendable for methods and key path literals