Merge branch 'bp/commit-p-editor' into maint

* bp/commit-p-editor:
run-command: mark run_hook_with_custom_index as deprecated
merge hook tests: fix and update tests
merge: fix GIT_EDITOR override for commit hook
commit: fix patch hunk editing with "commit -p -m"
test patch hunk editing with "commit -p -m"
merge hook tests: use 'test_must_fail' instead of '!'
merge hook tests: fix missing '&&' in test

diff --cc builtin/checkout.c
Simple merge

diff --cc builtin/commit.c
Simple merge

diff --cc commit.h
Simple merge