Fix the example for using a CDN with ActiveStorage
Fix the example for using a CDN with ActiveStorage

The code example relies on proper code being extracted
from the Rails source code. This bears the risk of the
code being extracted becoming outdated after a change
to Rails' source.

This change fixes such an inconsistency that was introduced
in the past.

georgeclaghorn/rails,BlakeWilliams/rails,georgeclaghorn/rails,rails/rails,Erol/rails,BlakeWilliams/rails,yawboakye/rails,BlakeWilliams/rails,georgeclaghorn/rails,kmcphillips/rails,Edouard-chin/rails,yawboakye/rails,esparta/rails,Edouard-chin/rails,MSP-Greg/rails,yahonda/rails,esparta/rails,Erol/rails,rails/rails,rails/rails,MSP-Greg/rails,yawboakye/rails,kmcphillips/rails,yawboakye/rails,yahonda/rails,rails/rails,esparta/rails,georgeclaghorn/rails,yahonda/rails,kmcphillips/rails,MSP-Greg/rails,kmcphillips/rails,Edouard-chin/rails,BlakeWilliams/rails,Erol/rails,Erol/rails,yahonda/rails,MSP-Greg/rails,Edouard-chin/rails,esparta/rails