[peewee] add typing for peewee.chunked

Reference: https://docs.peewee-orm.com/en/latest/peewee/api.html#chunked

> chunked(iterable, n)
>     Parameters * iterable – an iterable that is the source of the data to be chunked.
>                * n (int) – chunk size
>
>     Returns    a new iterable that yields n-length chunks of the source data.

Author: Psycojoker

stubs/peewee/peewee.pyi

@@ -45,7 +45,7 @@ IDENTIFIER_RE: Final[re.Pattern[str]]
 MODEL_BASE: Final = "_metaclass_helper_"
 
 def make_identifier(s: str) -> str: ...
-def chunked(it, n) -> Generator[list[Incomplete]]: ...
+def chunked(it: Iterable[_T], n: int) -> Generator[list[_T]]: ...
 
 class _callable_context_manager:
     def __call__(self, fn): ...