Fibonacci Sequence

Implement a generic Fibonacci<T> that takes a number T and returns its corresponding Fibonacci number.

The sequence starts:
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ...

For example

type Result1 = Fibonacci<3> // 2
type Result2 = Fibonacci<8> // 21