Docs: Update cluster.asciidoc
Docs: Update cluster.asciidoc

Clarify the preferencing.

Closes #9434

aparo/elasticsearch,aparo/elasticsearch,fubuki/elasticsearch,fubuki/elasticsearch,fubuki/elasticsearch,aparo/elasticsearch,fubuki/elasticsearch,aparo/elasticsearch,fubuki/elasticsearch,fubuki/elasticsearch,aparo/elasticsearch,aparo/elasticsearch