Add attribute templates to template vacuum (#13733)

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

source/_integrations/vacuum.template.markdown

@@ -51,6 +51,15 @@ vacuum:
         description: Defines a template to get the fan speed of the vacuum.
         required: false
         type: template
+      attribute_templates:
+        description: Defines templates for attributes of the sensor.
+        required: false
+        type: map
+        keys:
+          "attribute: template":
+            description: The attribute and corresponding template.
+            required: true
+            type: template          
       availability_template:
         description: Defines a template to get the `available` state of the component. If the template returns `true`, the device is `available`. If the template returns any other value, the device will be `unavailable`. If `availability_template` is not configured, the component will always be `available`.
         required: false
@@ -158,3 +167,28 @@ vacuum:
 ```
 
 {% endraw %}
+
+### Add Custom Attributes
+
+This example shows how to add custom attributes.
+
+{% raw %}
+```yaml
+vacuum:
+  - platform: template
+    vacuums:
+      living_room_vacuum:
+        value_template: "{{ states('sensor.vacuum_state') }}"
+        battery_level_template: "{{ states('sensor.vacuum_battery_level')|int }}"
+        fan_speed_template: "{{ states('sensor.vacuum_fan_speed') }}"
+        attribute_templates:
+          status: >-
+            {% if (states('sensor.robot_vacuum_robot_cleaner_movement') == "after" and states('sensor.robot_vacuum_robot_cleaner_cleaning_mode') == "stop")  %}
+              Charging to Resume
+            {% elif states('sensor.robot_vacuum_robot_cleaner_cleaning_mode') == "auto" %}
+              Cleaning
+            {% else %}
+              Charging
+            {% endif %}
+```
+{% endraw %}