2688. StartsWith

实现StartsWith<T, U>,接收两个string类型参数,然后判断T是否以U开头,根据结果返回true或false

例如:

type a = StartsWith<'abc', 'ac'> // expected to be false
type b = StartsWith<'abc', 'ab'> // expected to be true
type c = StartsWith<'abc', 'abcd'> // expected to be false