* feat(mr): support Forgejo/Codeberg pull request URLs
Codeberg and other Forgejo instances expose pull requests under
refs/pull/<id>/head instead of GitLab's refs/merge-requests/<id>/head,
so passing a Codeberg pull request URL to git mr fetched the wrong
ref. Recognize the /pulls/<id> URL shape and switch to the matching
ref for that case, leaving the GitLab URL and bare numeric id
behavior unchanged.
Closes#1213
* test(git-mr): cover Forgejo/Codeberg URLs, regenerate man docs
Add a bats test that exercises the pulls URL branch via a local
insteadOf remote rewrite (no real HTTP endpoint needed), and bring
git-mr.1/git-mr.html in line with the git-mr.md changes.
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Co-authored-by: vjymisal0 <vijay.looprai@gmail.com>