Book query using isbn doesn't work

[rkhwaja]

• Documentation error: the book function's second parameter is 'isbn', not 'book_isbn' as the documentation says
• Functional error - it looks like the code calls */book/isbn which isn't in the api according to https://www.goodreads.com/api. It looks like you have to lookup the goodreads book id from the isbn and then find the book by the goodreads id.