Feature Request: Interactively pick fixup revision

Hi,

first email to this list, so please forgive me if I'm doing something wrong.

My usual workflow is using `git commit --fixup <revision>` quite frequently, as it eases the code reviewing process and allows for a clean history later on.

One thing that is always cumbersome is to first find the SHA of the revision that I plan to commit a fixup to. I usually use git log and then copy the revision. I even wrote a script that eases this process using fzf: ``` #!/bin/bash

res=$(git log --oneline | fzf) ref=$(echo $res | cut -d ' ' -f1)

git commit --fixup ${ref} ```

I don't think fzf is really necessary here, but it speeds things up.

Anyhow, I'm really surprised that this isn't a feature of git. I could see a `git commit --fixup` (without a revision) or `git commit --fixup --interactive` open up the git log and let one pick the revision they want to commit a fixup to.

Cheers, Martin