Merge branch 'js/retire-preserve-merges'

The "--preserve-merges" option of "git rebase" has been removed.

* js/retire-preserve-merges:
  sequencer: restrict scope of a formerly public function
  rebase: remove a no-longer-used function
  rebase: stop mentioning the -p option in comments
  rebase: remove obsolete code comment
  rebase: drop the internal `rebase--interactive` command
  git-svn: drop support for `--preserve-merges`
  rebase: drop support for `--preserve-merges`
  pull: remove support for `--rebase=preserve`
  tests: stop testing `git rebase --preserve-merges`
  remote: warn about unhandled branch.<name>.rebase values
  t5520: do not use `pull.rebase=preserve`

t/t3418-rebase-continue.sh

@@ -119,20 +119,6 @@ test_expect_success 'rebase -i --continue handles merge strategy and options' '
 	test -f funny.was.run
 '
 
-test_expect_success REBASE_P 'rebase passes merge strategy options correctly' '
-	rm -fr .git/rebase-* &&
-	git reset --hard commit-new-file-F3-on-topic-branch &&
-	test_commit theirs-to-merge &&
-	git reset --hard HEAD^ &&
-	test_commit some-commit &&
-	test_tick &&
-	git merge --no-ff theirs-to-merge &&
-	FAKE_LINES="1 edit 2 3" git rebase -i -f -p -m \
-		-s recursive --strategy-option=theirs HEAD~2 &&
-	test_commit force-change &&
-	git rebase --continue
-'
-
 test_expect_success 'rebase -r passes merge strategy options correctly' '
 	rm -fr .git/rebase-* &&
 	git reset --hard commit-new-file-F3-on-topic-branch &&
@@ -268,7 +254,6 @@ test_rerere_autoupdate --apply
 test_rerere_autoupdate -m
 GIT_SEQUENCE_EDITOR=: && export GIT_SEQUENCE_EDITOR
 test_rerere_autoupdate -i
-test_have_prereq !REBASE_P || test_rerere_autoupdate --preserve-merges
 unset GIT_SEQUENCE_EDITOR
 
 test_expect_success 'the todo command "break" works' '