Picks property keys from the given Object type.
Example usage is shown below.
const T = Type.Object({
x: Type.Number(),
y: Type.Number(),
z: Type.Number()
})
const S = Type.Pick(T, Type.Union([ // const S: TObject<{
Type.Literal('x') // x: TNumber,
Type.Literal('y') // y: TNumber
])) // }>