Add lg_netcast turn_on_action configuration variable (#12075)

* Update lg_netcast.markdown

* ✏️ Tweak

This is more what I had in mind :)

* ❌ Remove part from first config example

Co-authored-by: Klaas Schoute <klaas_schoute@hotmail.com>

source/_integrations/lg_netcast.markdown

@@ -5,7 +5,7 @@ logo: lg.png
 ha_category:
   - Media Player
 ha_iot_class: Local Polling
-ha_release: '0.20'
+ha_release: 0.20
 ---
 
 The `lg_netcast` platform allows you to control a LG Smart TV running NetCast 3.0 (LG Smart TV models released in 2012) and NetCast 4.0 (LG Smart TV models released in 2013). For the new LG WebOS TV's use the [webostv](/integrations/webostv#media-player) platform.
@@ -16,7 +16,7 @@ To add a LG TV to your installation, add the following to your `configuration.ya
 # Example configuration.yaml entry
 media_player:
   - platform: lg_netcast
-    host: 192.168.0.20
+    host: IP_ADDRESS
 ```
 
 {% configuration %}
@@ -33,6 +33,10 @@ name:
   required: false
   default: LG TV Remote
   type: string
+turn_on_action:
+  description: Defines an [action](/docs/automation/action/) to turn the TV on.
+  required: false
+  type: string
 {% endconfiguration %}
 
 To get the access token for your TV configure the `lg_netcast` platform in Home Assistant without the `access_token`.
@@ -42,3 +46,18 @@ Just add the token to your configuration and restart Home Assistant and the medi
 <div class='note'>
   The access token will not change until you factory reset your TV.
 </div>
+
+## Advanced configuration
+
+The example below shows how you can use the `turn_on_action`
+
+```yaml
+# Example configuration.yaml entry
+media_player:
+  - platform: lg_netcast
+    host: 192.168.0.20
+    turn_on_action:
+      service: switch.turn_on
+      data:
+        entity_id: switch.tv_switch
+```