Rebase from squashed merge

[vanceism7]

Where I work, we've started a general policy to always squash merge our PRs. Sometimes I base new feature branches on unmerged PRs, and once those PRs are squash merged, it makes rebasing my feature branches back onto the master branch a bit more difficult.

Luckily I found this link which remedies the problem pretty well:
https://makandracards.com/makandra/45964-git-rebase-dependent-feature-branch-after-squash

I figured this would probably be a good candidate to add to the git flight rules. I just don't have time at the moment to make PR on this or I would have already. But I just wanted to put this up on the radar so maybe someone else or myself can add it at a later time.

Thanks!

[RichardLitt]

Sounds good to me! Labelled this accordingly, hope someone else takes it up.