Bump flake8-pyi to 23.11.0 (#10997)

stubs/fpdf2/fpdf/structure_tree.pyi

@@ -1,6 +1,6 @@
 from _typeshed import Incomplete, Unused
 from collections import defaultdict
-from collections.abc import Generator, Iterable
+from collections.abc import Iterable, Iterator
 
 from .encryption import StandardSecurityHandler
 from .syntax import PDFArray, PDFObject, PDFString
@@ -45,4 +45,4 @@ class StructureTreeBuilder:
     ) -> tuple[Incomplete, Incomplete]: ...
     def next_mcid_for_page(self, page_number: int) -> int: ...
     def empty(self) -> bool: ...
-    def __iter__(self) -> Generator[Incomplete, None, None]: ...
+    def __iter__(self) -> Iterator[Incomplete]: ...