Chore(mypy): Annotate None returns for typing improvements (#11213)

src/documents/views.py

@@ -1460,7 +1460,7 @@ class ChatStreamingView(GenericAPIView):
     ),
 )
 class UnifiedSearchViewSet(DocumentViewSet):
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, **kwargs) -> None:
         super().__init__(*args, **kwargs)
         self.searcher = None
 
@@ -1638,7 +1638,7 @@ class SavedViewViewSet(ModelViewSet, PassUserMixin):
             .prefetch_related("filter_rules")
         )
 
-    def perform_create(self, serializer):
+    def perform_create(self, serializer) -> None:
         serializer.save(owner=self.request.user)