`git machete diff`, contrary to the the docs, diffs HEAD (and not working directory) against fork-point

[PawelLipski]

https://git-machete.readthedocs.io/en/stable/#diff says:

Runs git diff of the given branch tip against its fork point or, if none specified, of the current working tree against the fork point of the currently checked out branch.

This is no longer the behavior of git machete diff however. Instead of calling git diff <fork-point>, it calls git diff <fork-point> <current-branch>. This is different because the latter does NOT take changes to working tree into account (and I'd expect to see them as well when doing git machete diff, analogously to git diff).