Dictionary subscript extension without Index

Edited for brevity from source. pointee could have been avoided by an = 0. I bet it was decided against because people don't teach each other to recognize empty square brackets. :dotted_line_face:

extension UnsafePointer where Pointee: ~Copyable {
  @_alwaysEmitIntoClient public var pointee: Pointee {
    @_transparent unsafeAddress { self }
  }
}

extension UnsafePointer where Pointee: ~Copyable {
  @_alwaysEmitIntoClient public subscript(i: Int) -> Pointee {
    @_transparent unsafeAddress { self + i }
  }
}