email: improve bytes handling (#9032)

stdlib/email/feedparser.pyi

@@ -20,5 +20,5 @@ class BytesFeedParser(Generic[_MessageT]):
     def __init__(self: BytesFeedParser[Message], _factory: None = ..., *, policy: Policy = ...) -> None: ...
     @overload
     def __init__(self, _factory: Callable[[], _MessageT], *, policy: Policy = ...) -> None: ...
-    def feed(self, data: bytes) -> None: ...
+    def feed(self, data: bytes | bytearray) -> None: ...
     def close(self) -> _MessageT: ...