Apply python formatting to unsynced .pyi files

Summary: [Folly] Apply python formatting to a few unsynced places in some `.pyi` files.

Reviewed By: markisaa

Differential Revision: D19249037

fbshipit-source-id: 6b14c5fedbee0f25a4b0fdfdd0f157e62a95a766

folly/python/iobuf.pyi

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Any, Union, Optional, Iterator, Hashable, Iterable
+from typing import Any, Hashable, Iterable, Iterator, Optional, Union
 
 class IOBuf(Hashable):
     def __init__(self, buffer: Union[IOBuf, bytes, bytearray, memoryview]) -> None: ...

folly/python/test/iobuf_helper.pyi

@@ -12,8 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from folly.iobuf import IOBuf
 from typing import List
 
+from folly.iobuf import IOBuf
+
 def get_empty_chain() -> IOBuf: ...
 def make_chain(data: List[IOBuf]) -> IOBuf: ...