feat: added rebase interactive

[kessejones]

adds the possibility to perform interactive rebase

[kessejones]

@sotte

[sotte]

I'll test it out during the next rebase. Thanks @kessejones.

[TimUntersberger]

What is the neovim RPC for? Is it just for testing?

Also please fix the linting errors.

Thank you!

[kessejones]

About neovim RPC

It is being used to communicate with the neovim process started by running git rebase -i.
To detect the opening of the git-rebase-todo file, I used the environment variables GIT_SEQUENCE_EDITOR and GIT_EDITOR to send a custom neovim command, which connects to the parent process and opens the file in a buffer, at the end of editing this file we send a signal to the child process to terminate it.

[TimUntersberger]

Thanks for explaining! 😄