Replace incomplete module markers (#14030)

stdlib/encodings/__init__.pyi

@@ -1,4 +1,3 @@
-from _typeshed import Incomplete
 from codecs import CodecInfo
 
 class CodecRegistryError(LookupError, SystemError): ...
@@ -7,4 +6,4 @@ def normalize_encoding(encoding: str | bytes) -> str: ...
 def search_function(encoding: str) -> CodecInfo | None: ...
 
 # Needed for submodules
-def __getattr__(name: str) -> Incomplete: ...
+def __getattr__(name: str): ...  # incomplete module