An abecedarian word is a word where all of its letters are arranged in alphabetical order. Examples of these words include:
Given a list of words, create a function which returns the longest abecedarian word. If no word in a list matches the criterea, return an empty string.
longest_abecedarian(["ace", "spades", "hearts", "clubs"]) ➞ "ace"
longest_abecedarian(["forty", "choppy", "ghost"]) ➞ "choppy"
longest_abecedarian(["one", "two", "three"]) ➞ ""