Fix pid=host example in documentation
Fix pid=host example in documentation

The existing example didn't illustrate how to
install strace in the container. In addition,
the rhel7 image used is no longer public (and maintained)
so not a good image to use in the example.

This updates the example to use htop (strace is
not working without disabling apparmor for the container)

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

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