When copying and pasting the code in the EXAMPLE
section, it would result in the following error:

"ngctl: send msg: Invalid argument"

The reason for this is the missing whitespace to
separate the arguments. When adding the whitespace,
the example works as intended.

Submitted by: lutz_donnerhacke.de
Approved by: bcr
Differential Revision: https://reviews.freebsd.org/D23773