Clean up some uses on 'an' in builder docs
Clean up some uses on 'an' in builder docs

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