Format markdown (#686)
Format markdown (#686)

Produced via:
  `prettier --write --prose-wrap=always $(find -name '*.md' | grep -v vendor | grep -v .github)`
/assign n3wscott
knative-sandbox/eventing-prometheus,knative-sandbox/eventing-gitlab,knative-sandbox/eventing-camel,knative-sandbox/eventing-natss,knative-sandbox/eventing-natss,knative-sandbox/eventing-camel,knative-sandbox/eventing-github,knative/eventing-contrib,knative-sandbox/eventing-prometheus,knative-sandbox/eventing-ceph,knative-sandbox/eventing-github,knative-sandbox/eventing-awssqs,knative/eventing-contrib,knative-sandbox/eventing-awssqs,knative-sandbox/eventing-couchdb,knative-sandbox/eventing-kafka,knative-sandbox/eventing-kafka,knative-sandbox/eventing-gitlab,knative-sandbox/eventing-couchdb,knative-sandbox/eventing-ceph