Merge branch 'ps/history-ergonomics-updates' into next

UI improvements for "git history reword".

* ps/history-ergonomics-updates:
  Documentation/git-history: document default for "--update-refs="
  builtin/history: rename "--ref-action=" to "--update-refs="
  builtin/history: replace "--ref-action=print" with "--dry-run"
  builtin/history: check for merges before asking for user input
  builtin/history: perform revwalk checks before asking for user input

Author: gitster

Documentation/git-history.adoc

@@ -8,7 +8,7 @@ git-history - EXPERIMENTAL: Rewrite history
 SYNOPSIS
 --------
 [synopsis]
-git history reword <commit> [--ref-action=(branches|head|print)]
+git history reword <commit> [--dry-run] [--update-refs=(branches|head)]
 
 DESCRIPTION
 -----------
@@ -60,13 +60,17 @@ The following commands are available to rewrite history in different ways:
 OPTIONS
 -------
 
-`--ref-action=(branches|head|print)`::
+`--dry-run`::
+	Do not update any references, but instead print any ref updates in a
+	format that can be consumed by linkgit:git-update-ref[1]. Necessary new
+	objects will be written into the repository, so applying these printed
+	ref updates is generally safe.
+
+`--update-refs=(branches|head)`::
 	Control which references will be updated by the command, if any. With
 	`branches`, all local branches that point to commits which are
 	descendants of the original commit will be rewritten. With `head`, only
-	the current `HEAD` reference will be rewritten. With `print`, all
-	updates as they would be performed with `branches` are printed in a
-	format that can be consumed by linkgit:git-update-ref[1].
+	the current `HEAD` reference will be rewritten. Defaults to `branches`.
 
 GIT
 ---