vm-host parameters help is wrong

$ maas root vm-host parameters
usage: maas root vm-host parameters [--help] [-d] [-k] id [data ...]

Obtain VM host parameters
...
Note: This method is reserved for admin users.

the following arguments are required: id, data

However data is not required, it is not even supposed to do anything

`vm-host parameters id` returns all parameters in one output

`vm-host parameters id certificate` says
'certificate' is not a name=value or name@=filename pair

Eithr parameter command needs to support data and return just that field from the output or help should be corrected to not suggest `data` is a valid argument or that it is required argument.

To be clear parameters -h shows `data` as argument and parameters without specifying id says id and data are required arguments