Merge branch 'jn/update-contrib-example-merge'

* jn/update-contrib-example-merge: (24 commits) merge script: learn --[no-]rerere-autoupdate merge script: notice @{-1} shorthand merge script: handle --no-ff --no-commit correctly merge script: --ff-only to disallow true merge merge script: handle many-way octopus merge script: handle -m --log correctly merge script: forbid merge -s index merge script: allow custom strategies merge script: merge -X<option> merge script: improve log message subject merge script: refuse to merge during merge merge script: tweak unmerged files message to match builtin merge script: --squash, --ff from unborn branch are errors fmt-merge-msg -m to override merge title merge-base --independent to print reduced parent list in a merge merge-base --octopus to mimic show-branch --merge-base Documentation: add a SEE ALSO section for merge-base t6200 (fmt-merge-msg): style nitpicks t6010 (merge-base): modernize style t7600 (merge): test merge from branch yet to be born ...