Minor tweak to build -f text to make it clear Dockerfile is in context
Minor tweak to build -f text to make it clear Dockerfile is in context

Closes #11289

Signed-off-by: Doug Davis <ff3bde741799c0eff815b83a54eda3fc494df54f@us.ibm.com>

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