The custom help() is replaced by the common verb help, which derives the
synopsis, abstract, and option list from the verb declaration in
udevadm.c and the "udevadm-control" option namespace. The synopsis
makes use of the new nulstr-argspec functionality:
> udevadm [OPTION…] lock [OPTION…] COMMAND
> udevadm [OPTION…] lock [OPTION…] --print