rotate_pairs does not find all possible rotate pairs

[DavidVFitzGerald]

It appears that the function rotate_pairs (solution for Exercise 11.5) does not check for all rotated words, due to the stop argument of the range being 14 instead of 26. For example, passing the word "act" as argument should print out "act 24 yar", but currently does not print out anything. It's also possible to avoid iterating through all possible rotated words for each word in the list of words.