In a sorted circular array of letters, find the next letter after
target.Example 1
Input: letters = ["c","f","j"], target = "a"
Output: c
Explanation: The next letter after a is c.
Output: c
Explanation: The next letter after a is c.
Example 2
Input: letters = ["c","f","j"], target = "c"
Output: f
Explanation: The next letter after c is f.
Output: f
Explanation: The next letter after c is f.