Update (add new screenshot and fix service name) (#5361)

* Update (add new screenshot and fix service name)

* Update link

source/_components/notify.mqtt.markdown

@@ -14,7 +14,7 @@ ha_iot_class: depends
 
 The MQTT notification support is different than the other [notification](/components/notify/) platforms. It is a service. This means that you don't have to create a configuration entry but you need to provide more details when calling the service.
 
-**Call Service** section from the **Developer Tools** allows you to send MQTT messages. Choose *mqtt/publish*  from the list of **Available services:** and enter something like the sample below into the **Service Data** field and hit **CALL SERVICE**.
+**Call Service** section from the **Developer Tools** allows you to send MQTT messages. Choose *mqtt.publish*  from the list of **Available services:** and enter something like the sample below into the **Service Data** field and hit **CALL SERVICE**.
 
 ```json
 {"payload": "Test message from HA", "topic": "home/notification", "qos": 0, "retain": 0}
@@ -24,7 +24,13 @@ The MQTT notification support is different than the other [notification](/compon
   <img src='/images/screenshots/mqtt-notify.png' />
 </p>
 
-Using the [REST API](/developers/rest_api/#post-apiservicesltdomainltservice) to send a message to a given topic.
+The same will work for automations.
+
+<p class='img'>
+  <img src='/images/screenshots/mqtt-notify-action.png' />
+</p>
+
+Using the [REST API](https://developers.home-assistant.io/docs/en/external_api_rest.html) to send a message to a given topic.
 
 ```bash
 $ curl -X POST -H "x-ha-access: YOUR_PASSWORD" \