Update Transition guide.md
Update Transition guide.md

I updated the information on how to get data from an instance of `PPUsdlRecognizerResult`.  This may need to be removed once the framework is updated to include a `data` selector in `PPUsdlRecognizerResult`.

-- Austin O'Neil, DealerSocket
PDF417/pdf417-ios,PDF417/pdf417-ios,PDF417/pdf417-ios