Use Incomplete instead of Any in __getattr__ (#8903)

stubs/flake8-builtins/flake8_builtins.pyi

@@ -1,4 +1,5 @@
 import ast
+from _typeshed import Incomplete
 from collections.abc import Generator
 from typing import Any, ClassVar
 
@@ -8,4 +9,4 @@ class BuiltinsChecker:
     def __init__(self, tree: ast.AST, filename: str) -> None: ...
     def run(self) -> Generator[tuple[int, int, str, type[Any]], None, None]: ...
 
-def __getattr__(name: str) -> Any: ...  # incomplete (other attributes are normally not accessed)
+def __getattr__(name: str) -> Incomplete: ...  # incomplete (other attributes are normally not accessed)