Preparations for the Big Reformat (#4228)

A few comments between imports were removed or moved to the top of the
import block, due to behavioral differences between black and isort. See
psf/black#251 for details.

In two instances @overloads at the top of the file needed to be moved
due to psf/black#1490.

stdlib/3/ast.pyi

@@ -1,15 +1,16 @@
-import sys
 # Rename typing to _typing, as not to conflict with typing imported
 # from _ast below when loaded in an unorthodox way by the Dropbox
 # internal Bazel integration.
-import typing as _typing
-from typing import Any, Iterator, Optional, TypeVar, Union, overload
-from typing_extensions import Literal
 
 # The same unorthodox Bazel integration causes issues with sys, which
 # is imported in both modules. unfortunately we can't just rename sys,
 # since mypy only supports version checks with a sys that is named
 # sys.
+import sys
+import typing as _typing
+from typing import Any, Iterator, Optional, TypeVar, Union, overload
+from typing_extensions import Literal
+
 from _ast import *  # type: ignore
 
 if sys.version_info >= (3, 8):

stdlib/3/asyncio/events.pyi

@@ -8,11 +8,11 @@ from asyncio.protocols import BaseProtocol
 from asyncio.tasks import Task
 from asyncio.transports import BaseTransport
 from asyncio.unix_events import AbstractChildWatcher
+from _typeshed import FileDescriptorLike
+
 if sys.version_info >= (3, 7):
     from contextvars import Context
 
-from _typeshed import FileDescriptorLike
-
 _T = TypeVar('_T')
 _Context = Dict[str, Any]
 _ExceptionHandler = Callable[[AbstractEventLoop, _Context], Any]

stdlib/3/os/__init__.pyi

@@ -7,7 +7,6 @@ from typing import (
 )
 from _typeshed import AnyPath
 
-# Re-exported names from other modules.
 from builtins import OSError as error
 from . import path as path