Clean up of API reference page to match headings on API specs page
Clean up of API reference page to match headings on API specs page

bug: #1173272

Change-Id: I99415b3610bad4ca3e5be2f65f1ef548bd1ed92b
author: Diane Fleming

DonSchenck/api-site,Tesora/tesora-api-site,Tesora/tesora-api-site,varunarya10/api-site,DonSchenck/api-site,JioCloud/api-site,dreamhost/api-site,dreamhost/api-site,rackerlabs/api-site,dreamhost/api-site,rackerlabs/api-site,openstack/api-site,rackerlabs/api-site,openstack/api-site,openstack/api-site,dreamhost/api-site,Tesora/tesora-api-site,DonSchenck/api-site,Tesora/tesora-api-site,dreamhost/api-site,dreamhost/api-site,rackerlabs/api-site,Tesora/tesora-api-site,dreamhost/api-site,Tesora/tesora-api-site,DonSchenck/api-site,varunarya10/api-site,openstack/api-site,DonSchenck/api-site,Tesora/tesora-api-site