Create a function that takes an array and a string as arguments and returns the index of the string.
FindIndex(new string[] {"hi", "edabit", "fgh", "abc"}, "fgh") ➞ 2
FindIndex(new string[] {"Red", "blue", "Blue", "Green"}, "blue") ➞ 1
FindIndex(new string[] {"a", "g", "y", "d"}, "d") ➞ 3
FindIndex(new string[] {"Pineapple", "Orange", "Grape", "Apple"}, "Pineapple") ➞ 0return the result.