Document switch entity for add-ons (#40661)

Author: felipecrs

source/_integrations/hassio.markdown

@@ -5,6 +5,7 @@ ha_category:
   - Backup
   - Binary sensor
   - Sensor
+  - Switch
   - Update
 ha_iot_class: Local Polling
 ha_release: 0.42
@@ -15,6 +16,7 @@ ha_platforms:
   - binary_sensor
   - diagnostics
   - sensor
+  - switch
   - update
 ha_codeowners:
   - '@home-assistant/supervisor'
@@ -84,6 +86,14 @@ For Home Assistant OS Supervisor provides following binary sensors:
 | ------- | ------------------ | ----------- |
 | Update Available | no | Whether there is an update available for OS
 
+## Switch entities
+
+For each installed add-on, the following switch is available:
+
+| Switch | Enabled by default | Description |
+| ------- | ------------------ | ----------- |
+| Running | no | Shows whether the add-on is running or not, and allows you to start or stop the add-on depending on its current state. |
+
 ## Update entities
 
 For all your installed add-ons, Home Assistant Core, Home Assistant Supervisor, and for the Home Assistant Operating System (if you are running that), this integration will provide [update](/integrations/update) entities that provide information about pending updates, and will allow you to update to them.