Update the HOT reference guide
Update the HOT reference guide

Change-Id: If7a4aa453ab2bd0ba16291b800770d3eb233e8c3

openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,saeki-masaki/openstack-manuals,saeki-masaki/openstack-manuals,gongysh2004/openstack-manual,gongysh2004/openstack-manual,openstack/openstack-manuals,Akasurde/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,kairoaraujo/openstack-manuals,potsmaster/openstack-manuals,kairoaraujo/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,potsmaster/openstack-manuals,Akasurde/openstack-manuals