Add constructor return type in integrations L-N (#50888)

* Add constructor return type in integrations L-N

* Small fix

homeassistant/components/notion/__init__.py

@@ -141,7 +141,7 @@ class NotionEntity(CoordinatorEntity):
         system_id: str,
         name: str,
         device_class: str,
-    ):
+    ) -> None:
         """Initialize the entity."""
         super().__init__(coordinator)
         self._attrs = {ATTR_ATTRIBUTION: DEFAULT_ATTRIBUTION}