Update baf.markdown for occupancy sensor (#23541)

Co-authored-by: J. Nick Koston <nick@koston.org>

source/_integrations/baf.markdown

@@ -2,6 +2,7 @@
 title: Big Ass Fans
 description: Instructions on how to integrate BAF devices into Home Assistant.
 ha_category:
+  - Binary Sensor
   - Climate
   - Fan
   - Light
@@ -17,6 +18,7 @@ ha_codeowners:
 ha_domain: baf
 ha_config_flow: true
 ha_platforms:
+  - binary_sensor
   - climate
   - fan
   - light
@@ -36,11 +38,15 @@ Integrates [Big Ass Fans](https://www.bigassfans.com/) devices into Home Assista
 
 ## Platforms
 
+### Binary Sensor
+
+For devices that support Auto Comfort and are running firmware 3.1 or later, an occupancy sensor entity is available. The sensor has a hold time of about 5 minutes and pushes state updates.
+
 ### Climate
 
 For devices that support Auto Comfort, a climate entity allows adjusting the target temperature.
 
-## Number
+### Number
 
 Adjusting the minimum and maximum speed for devices that support Auto Comfort is available.