The shell function git-signoff was replaced with gits builtin
functionality in 09ef4d4d93 ("git: Replace git-signoff with `rebase
--signoff`").
Also adjust the example in the new commment.
The shell function git-signoff was replaced with gits builtin
functionality in 09ef4d4d93 ("git: Replace git-signoff with `rebase
--signoff`").
Also adjust the example in the new commment.