Add trend config flow (#28813)

source/_integrations/trend.markdown

@@ -4,13 +4,15 @@ description: Instructions on how to integrate Trend binary sensors into Home Ass
 ha_category:
   - Binary sensor
   - Utility
+  - Helper
 ha_release: 0.28
 ha_iot_class: Calculated
 ha_quality_scale: internal
 ha_domain: trend
 ha_platforms:
   - binary_sensor
-ha_integration_type: integration
+ha_config_flow: true
+ha_integration_type: helper
 ha_codeowners:
   - '@jpbede'
 ---
@@ -21,7 +23,19 @@ at least two updates of the underlying sensor to establish a trend.
 Thus it can take some time to show an accurate state. It can be useful
 as part of automations, where you want to base an action on a trend.
 
-## Configuration
+{% include integrations/config_flow.md %}
+{% configuration_basic %}
+Name:
+  description: The name the sensor should have. You can change it again later.
+Entity that the sensor tracks:
+  description: The sensor entity that is to be tracked and whose trend is to be detected.
+Attribute of the entity that the sensor tracks:
+  description: The attribute of the previous selected sensor entity that this sensor tracks. If no attribute is specified then the sensor will track the state.
+Invert the result:
+  description: Invert the result. A `true` value would mean descending rather than ascending.
+{% endconfiguration_basic %}
+
+### YAML Configuration
 
 To enable Trend binary sensors in your installation,
 add the following to your `configuration.yaml` file: