Reverse the character array `s` in-place and return it. Variant **#21**.
Example 1
Input: s = ["v","a","r","i","a","n","t","2","1","c","o","d","e"]
Output: ["e","d","o","c","1","2","t","n","a","i","r","a","v"]
Constraints
Acceptance: 66% · Topics: string, two-pointers