xmltodict: improve parse input types (#9018)

stubs/xmltodict/xmltodict.pyi

@@ -1,6 +1,7 @@
-from _typeshed import SupportsRead, SupportsWrite
+from _typeshed import ReadableBuffer, SupportsRead, SupportsWrite
 from collections import OrderedDict
 from collections.abc import Mapping
+from types import GeneratorType
 from typing import Any, overload
 
 __license__: str
@@ -8,7 +9,7 @@ __license__: str
 class ParsingInterrupted(Exception): ...
 
 def parse(
-    xml_input: str | bytes | SupportsRead[bytes],
+    xml_input: str | ReadableBuffer | SupportsRead[bytes] | GeneratorType[ReadableBuffer, Any, Any],
     encoding: str | None = ...,
     expat: Any = ...,
     process_namespaces: bool = ...,