adds Databroker storage connection string description

Author: ZPain8464

content/docs/reference/reference.json

@@ -739,6 +739,7 @@
   "data-broker-storage-connection-string": {
     "id": "data-broker-storage-connection-string",
     "title": "Databroker Storage Connection String",
+    "description": "Sets Postgres connection string to connect Databroker service to storage backend",
     "path": "/databroker#databroker-storage-connection-string",
     "services": [],
     "type": "string"