Mark calendar methods and properties as mandatory in pylint plugin (#145271)

pylint/plugins/hass_enforce_type_hints.py

@@ -985,6 +985,7 @@ _INHERITANCE_MATCH: dict[str, list[ClassTypeHintMatch]] = {
                         3: "datetime",
                     },
                     return_type="list[CalendarEvent]",
+                    mandatory=True,
                 ),
             ],
         ),