Git-machete

- added: git config keys `machete.github.prDescriptionIntroStyle` and `machete.gitlab.mrDescriptionIntroStyle`
- added: ability to turn off PR/MR description intro completely by setting the git config key to `none` (suggested by tir38)
- added: ability to include downstream PRs/MRs in PR/MR description intro by setting the git config key to `full` (suggested by aouaki)
- changed: layout and ordering of PRs/MRs in PR/MR description intro to better match `git machete status`

- added: ability to specify pass-through flags in `diff` and `log`, for example `git machete diff -- file.txt`, `git machete log -- --patch` (partly contributed by tdyas)

- added: git config key `http.sslVerify` is honored when connecting to GitHub and GitLab APIs (suggested by scamden)

- fixed: avoid detecting a cycle when there's a PR/MR from `main` or `master` in a fork to the original repo (reported by Joibel)
- fixed: `git machete git{hub,lab} create-{pr,mr}` no longer fails when creating a PR/MR across forks; instead, a forked PR is created (reported by cspotcode)
- improved: `git machete git{hub,lab} checkout-{prs,mrs}` only adds annotations to affected branches (and not to every branch)

- improved: performance of listing commits for red-edge branches on large repos
- improved: message in case of missing `.git/machete` file suggests to use `git machete git{hub,lab} checkout-{prs,mrs}`
- fixed: pass `-c log.showSignature=false` to all `git` invocations to hide GPG signatures in logs; if `log.showSignature` were set to a value equivalent to `true` in a user's `git` configuration, the GPG signatures shown in logs would cause errors in `git log` and `git reflog` parsing internal to `git machete` (reported and contributed by goxberry)

- fixed: parsing of multiline git config keys (reported by saveman71)