The custom help() is replaced by a COMMAND() description, and
--introspect-cli is added. The "Options" group marker after --help/--version
is dropped, so that all options are listed in one section after the verbs.
The synopsis now uses the generic "[OPTION…] COMMAND …" form: a bare
VERSION is not accepted as the first argument, and the man page does not
list it either. --help now goes through the pager, like other commands
with --no-pager.