Make a function called `letterSpaceNumber` that receives a string and returns an
array with every instance of a letter, followed by a space, followed by a number
only if that number has only one digit and is not followed by any letter.
Create a function named `letterSpaceNumber` that accepts a string; returning an array with every instance of a letter, followed by a space, followed by a number, only if that number has only one digit, and is not followed by any letter.