6. Search Insert Position
Given a sorted array and a target value, return its index or the index where it would be inserted.
Example 1:
Input: nums = [1,3,5,6], target = 5 Output: 2
Example 2:
Input: nums = [1,3,5,6], target = 2 Output: 1
Constraints:
1 <= nums.length <= 10^4