Should echo commit message when commit is denied

[m-o-e]

Overcommit should echo the user provided commit message to stdout
whenever it declines a commit, so it can be copy/pasted for a new attempt.

Currently all input is lost when a validation fails, which is very frustrating
and discourages users from writing elaborate commit messages.

[sds]

I agree this isn't a great experience, @m-o-e.

Perhaps we can leverage Git's core.editor configuration to re-open the editor you used to write the commit message (with the commit message you already wrote) in the event of a failed hook run.

Would welcome a pull request here!

[henrahmagix]

Added a PR in #519

[henrahmagix]

@sds I'd love to get some feedback on #519 please =)

[sds]

Implemented in #519