Merge branch 'maint'

* maint:
  user-manual: recovering from corruption
  user-manual: clarify language about "modifying" old commits
  user-manual: failed push to public repository
  user-manual: define "branch" and "working tree" at start
  git-checkout: describe detached head correctly

git-checkout.sh

@@ -175,7 +175,7 @@ detach_warn=
 describe_detached_head () {
 	test -n "$quiet" || {
 		printf >&2 "$1 "
-		GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2"
+		GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2" --
 	}
 }