Finish the function numberToOrdinal, which should take a number and return it as a string with the correct ordinal indicator suffix (in English). That is:
- numberToOrdinal(1) ==> '1st'
- numberToOrdinal(2) ==> '2nd'
- numberToOrdinal(3) ==> '3rd'
- numberToOrdinal(4) ==> '4th'