devel/freebsd-git-devtools: Update to 2024-12-03 snapshot, d6ed5ff4

Base commits since last update:
d6ed5ff4ac7d - git-arc: fix diff2reviewers() with multiple reviewers
976ab1425da4 - git-arc: Document how a reviewer group can be referenced
2c2f741363a9 - mfc-candidates: Improve hash expansion
586c651f2baa - mfc_candidates: remove leftover message
48f3fcabea80 - mfc-candidates: Convert to Lua
9e84289f2c7e - git-arc: Prefer echo over printf
2377c19a8c37 - git-arc: Trap on every mktemp
019981e00f23 - git-arc: Fix typo s/Truning/Turning/
aa90b92ac289 - git-arc: Fix find_author() for external users
66a56e411ced - mfc-candidates: Support GitHub mirror naming conventions
3ab8697d9e45 - git-arc: Do not echo unescaped literals to jq
7d875598fc9f - git-arc: Make patch with reviewers more portable
c008b8f585b6 - git-arc: minor manpage edits
87e5b17c149e - prepare-commit-msg: add 50 column marker
a2c88e0d47ac - git-arc: Use a helper function to fetch boolean config variables
41d6858ebd6a - git-arc.1: list width typo
2f68f6474e41 - git-arc: Add list mode support for the update command

While here, update pkg-descr.

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