Vscode-git-graph: Add "rebase --onto" branch action

[borekb]

When in a situation like this (from Git docs):

                            H---I---J topicB
                           /
                  E---F---G  topicA
                 /
    A---B---C---D  master

I'd like to be able to right-click on topicB and select a new command Rebase onto master which would invoke git rebase --onto master topicA topicB.

This is arguably an idealistic / simplified scenario but probably the most common one. I think that for the first iteration of this feature, if done at all, could even hardcode the master branch and only offer the menu item when the layout like above is detected (there's exactly one head between the current branch and master).

[mhutchie]

Thanks for raising this feature request!

If this was to be included in Git Graph, I wouldn’t want to hardcode the master branch (even for just a first iteration) as many users already work from develop branches instead. All of the context menu items currently available are completely generic to maximise the potential value they can add to the largest volume of users.

Note to other users reading this feature request: To me this request seems quite specific, and I’m unsure how many users would regularly use this feature to make it worth being included in Git Graph (given the potential complexity to make this action generic enough to benefit everyone). If you’d regularly use this feature, please like this first comment in this thread so I can gauge community interest. If enough users express interest, I’d be more than happy to implement this feature in Git Graph.

[MetRonnie]

Having git rebase --onto would be really nice, though I'm not sure how it could work. Often I'm rebasing a branch from an arbitrary commit onto another branch. Perhaps there could be a context menu item called Rebase onto... and then it would prompt you to click on the last commit you don't want moved, followed by the commit/branch on which to rebase?