cabal-diff: reporting of deleted modules

[harendra-kumar]

We deleted the Streamly.Tutorial module in the new release. But it is reported as follows:

++ wSerial :: IsStream t => t m a -> t m a -> t m a
    Streamly.Tutorial
@@@ Streamly.Unicode.Stream

It will be helpful if there is some annotation indicating that this is deleted.

[phadej]

It's reported that way because it didn't exported anything. Not good, but quite a corner case.