Documentation for device trackers in tplink_omada (home-assistant#32314)

* Add device tracker documentation for tplink_omada

* Update tplink_omada tracker documentation to reflect reality

* Fix casing

source/_integrations/tplink_omada.markdown

@@ -59,3 +59,11 @@ Controller versions 5.1.0 and later are supported.
 - WAN Port Connect/Disconnect switches
 - LAN Port PoE activity sensor
 - Firmware Update
+
+### Device trackers
+
+The integration can track Wi-Fi devices connected to access points managed by the TP-Link Omada controller. All known Wi-Fi clients will be initially created in a disabled state. You then need to enable the entities that you want to track.
+
+If you want to increase the polling frequency of client updates, follow [these instructions](https://www.home-assistant.io/common-tasks/general/#defining-a-custom-polling-interval). You only need to request a refresh from one of the tracked devices, all of the tracked devices will be refreshed at the same time.
+
+Note: The TP-Link Omada controller takes a few minutes to detect when a client disconnects from the Wi-Fi network, even with more regular polling updates.