Add prefix "$" for command examples
Add prefix "$" for command examples

This commits adds "$" as a prefix for command examples and align with
4 whitespaces.

Change-Id: Id9378c1ea020ba9577d392c2082db3e60495a0d8

stackforge/monasca-log-api,openstack/monasca-log-api,openstack/monasca-log-api,stackforge/monasca-log-api,openstack/monasca-log-api,stackforge/monasca-log-api