Re-pitch of init(unsafeUninitializedCapacity:initializingWith:) (#993)
Re-pitch of init(unsafeUninitializedCapacity:initializingWith:) (#993)

* First cut of initializer-only

* Update the try-at-home implementation

* Add vDSP example

* tweak example

* Fix the try-this-at-home version again

Don't leak memory and provide the correct throwing semantics.

* Remove vestiges of the proposed method

* Update link to implementation PR

* Remove the (needs updating) bit

* Update title

natecook1000/swift-evolution,apple/swift-evolution,abertelrud/swift-evolution,ddunbar/swift-evolution,abertelrud/swift-evolution,ddunbar/swift-evolution,Nirma/swift-evolution,apple/swift-evolution,DevAndArtist/swift-evolution,anandabits/swift-evolution,natecook1000/swift-evolution,anandabits/swift-evolution,DevAndArtist/swift-evolution,Nirma/swift-evolution,hartbit/swift-evolution,hartbit/swift-evolution