Updated docs README with instructions to preview the generated manfile, and where to get the one generated by sphinx.
Updated docs README with instructions to preview the generated manfile, and where to get the one generated by sphinx.

allencloud/cli,redpanda/cli,docker/cli,e11137/cli,riyazdf/cli,riyazdf/cli,docker/cli,ashfall/cli,allencloud/cli,ashfall/cli,thaJeztah/cli,e11137/cli,Zebrilee/cli,cpuguy83/cli,redpanda/cli,Zebrilee/cli,dnephin/cli,thaJeztah/cli,dnephin/cli,cpuguy83/cli