Update unique-config-entry rule

Author: joostlek

docs/core/integration-quality-scale/rules/unique-config-entry.md

@@ -17,6 +17,8 @@ This can lead to duplicated devices and entities with unique identifiers collidi
 Any discovery flow must also ensure that a config entry is uniquely identifiable, as otherwise, it would discover devices already set up.
 
 To prevent this, we need to ensure that the user can only set up a device or service once.
+Trying to set up a device or service that is already set up should be prevented by the integration.
+This should be handled by the reconfiguration flow, in where we can be more consistent with what gets updated.
 
 ## Example implementation