fix: type annotation default for named: Literal[False] was missing in DataFrame.iter_rows (#2778)

Author: MarcoGorelli

narwhals/dataframe.py

@@ -1196,7 +1196,7 @@ def iter_columns(self) -> Iterator[Series[Any]]:
 
     @overload
     def iter_rows(
-        self, *, named: Literal[False], buffer_size: int = ...
+        self, *, named: Literal[False] = ..., buffer_size: int = ...
     ) -> Iterator[tuple[Any, ...]]: ...
 
     @overload