docs/plugins: sync docs with changes site changes
docs/plugins: sync docs with changes site changes

This patch applies the same changes from the review of
https://github.com/weaveworks/scope/pull/2008

kinvolk/scope,alban/scope,kinvolk/scope,alban/scope,paulbellamy/scope,weaveworks/scope,paulbellamy/scope,alban/scope,alban/scope,kinvolk/scope,paulbellamy/scope,kinvolk/scope,weaveworks/scope,paulbellamy/scope,kinvolk/scope,weaveworks/scope,kinvolk/scope,alban/scope,weaveworks/scope,paulbellamy/scope,weaveworks/scope,paulbellamy/scope,weaveworks/scope,alban/scope