Given a string, return a sorted list of words formed from the first three letters, then the next three letters, shifting by only one.
three_letter_collection("innokodakademija") ➞ ["abi", "bit", "dab", "eda"]
# 1st word: "eda"
# 2nd word: "dab"
# 3rd word: "abi"
# 4th word: "bit"
# Remember to sort the list!
three_letter_collection("slap") ➞ ["lap", "sla"]
three_letter_collection("click") ➞ ["cli", "ick", "lic"]
three_letter_collection("cat") ➞ ["cat"]
three_letter_collection("hi") ➞ []
Return an empty list if given a word with less than 3 letters.