Resolve #2880154 "Revisionable comments"

Closes #2880154

core/modules/comment/config/schema/comment.schema.yml

@@ -40,6 +40,9 @@ comment.type.*:
     description:
       type: text
       label: 'Description'
+    new_revision:
+      type: boolean
+      label: 'Whether a new revision should be created by default'
 
 field.storage_settings.comment:
   type: mapping