[doc] Add reference to full set of pulsar connector
### Motivation
Pulsar supports 30+ connectors, we need to let users know it.
### Modifications
Add reference to the IO Hub that Pulsar supports.
@@ -4,7 +4,7 @@ title: Built-in connector
sidebar_label: Built-in connector
---
-Pulsar distribution includes a set of common connectors that have been packaged and tested with the rest of Apache Pulsar. These connectors import and export data from some of the most commonly used data systems.
+Pulsar distribution includes a set of common connectors that have been packaged and tested with the rest of Apache Pulsar. These connectors import and export data from some of the most commonly used data systems. For a full set of third-party connectors that Pulsar supports, refer to [StreamNative Hub](https://hub.streamnative.io/).
Using any of these connectors is as easy as writing a simple connector and running the connector locally or submitting the connector to a Pulsar Functions cluster.
