Create a function that returns a capitalized version of the string passed. The first letter of each word in the string should be capitalized while the rest should be in lowercase.
emphasize("hello world!") ➞ "Hello World!"
emphasize("GOOD MORNING!") ➞ "Good Morning!"
emphasize("I AM, BUT aLL yOuRs, TESH!") ➞ "I Am, But All Yours, Tesh!"
emphasize("99 red balloons!") ➞ "99 Red Balloons!"