feature request: consider picked commits in "branch --contains"

Hi,

there are development workflows where a feature or fix is by definition implemented in the dev branch and perhaps picked into a stable/rc branch. A question often being asked in such a workflow is "Is this fix in this stable branch?". Usually I would call "git branch -r --contains $commit" to figure this out, but this command does not work in such workflows because it's a different commit since it was picked. git-log knows the --cherry-pick option to identify commits with identical changes. Wouldn't it be nice to say "git branch --cherry-pick --contains $commit" to see branches containing a commit even if the commit was picked?!

Ralf