This change makes the user guide page more readable and results in a
command line usage page which is easy to navigate as all sub-commands
can be found in the left-hand outline panel.
Also fix the layout of the environment variables table by using a
replacement.
Signed-off-by: Paul Barker <pbarker@konsulko.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
