Make formatting problems easier to spot. (#588)
Make formatting problems easier to spot. (#588)

Currently the if a file needs formatting it prints the entire file.
Even when the step fails it is difficult to spot what is failing and
what needs to get done.
flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon