Ability to edit message from git rebase --interactive.

Hello.

I use git in a workflow in wich we often need to edit the message logs of some 
commits.
The way we do it is using git rebase -i    and choose edit.   
But then you need to do git commit --amend and git rebase --continue,  which 
is error prone and add more useless steps.

The attached patch add a new keyword to git rebase interactive to just edit 
the message log.

I was told on IRC that this has been discussed already not so long ago, and 
looking on the archive[1], all i seen was bikesheeding .  Here is a patch :-)

Do you think it make sens to have that in git?

Please CC me replies.

-- 
Olivier


[1] http://thread.gmane.org/gmane.comp.version-control.git/105738
(my patch is different from this one as it adds a new keyword rather than 
change the behavior of one existing one)