Create a function that takes a string and checks if every single character is preceded and followed by a character adjacent to it in the english alphabet.
Example: "b" should be preceded and followed by ether "a" or "c" (abc || cba || aba || cbc == True but abf || zbc == False).
neighboring("aba") ➞ True
neighboring("abcdedcba") ➞ True
neighboring("efghihfe") ➞ False
neighboring("abc") ➞ True
neighboring("qrstuv") ➞ True
neighboring("mnopqrstsrqponm") ➞ True
All test cases will consist of lower case letters only.