swift234

stdlib: Add unavailable declarations for APIs renamed in SE-0118

Sequence.sort(_:) => sorted(by:)
Sequence.sort() => sorted()
Sequence.elementsEqual(_:isEquivalent) => elementsEqual(_:by:)
Sequence.contains(_:) => contains(where:)
Sequence reduce(_:combine:) => reduce(_:_:)
UnicodeCodec.encode(_:output:) => encode(_:into:)
ManagedBuffer.create(_:initialValue:)
  => create(minimumCapacity:makingHeaderWith:)
ManagedBufferPointer.init(bufferClass:minimumCapacity:initialValue)
  => init(bufferClass:minimumCapacity:makingHeaderWith:)