Would be useful if cherry-picker messages were more prominent

[smontanaro]

As people have learned I am not always the most observant person in the world. My initial attempts to use cherry-picker were complicated by the fact that I paid attention to messages from git cherry-pick, not cherry-picker's own messages. It would be nice if the message sources were better distinguished, either by dimming the messages from git cherry-pick or by coloring the messages from cherry-picker.

If you think something like this would be useful, I could work on a PR. It seems that any desired changes would be straightforward, as current console output already uses click.echo().

[smontanaro]

Here's more-or-less what I have in mind. I just created a trivial script using click.secho echoing
some existing output from a cherry_picker run.
clickex.txt