- added: `git machete github create-pr` adds a comment linking the PR to its base PR; `github retarget-pr` keeps that comment up to date (suggested by guyboltonking)
- added: new subcommand `git machete github restack-pr`, which (force-)pushes and retargets the PR, without adding code owners as reviewers in the process (suggested by raylu)
- improved: when running `git machete squash` against a root branch, the error message suggests using `--fork-point=...` flag (suggested by levinotik)
- improved: simplified & clarified docs in multiple places (partly suggested by kgadek)