Remove a bunch of unused imports (#3323)

stdlib/3/asyncio/coroutines.pyi

@@ -1,4 +1,4 @@
-from typing import Any, Callable, Generator, List, TypeVar
+from typing import Any, Callable, List, TypeVar
 
 __all__: List[str]
 

stdlib/3/asyncio/futures.pyi

@@ -1,5 +1,5 @@
 import sys
-from typing import Any, Union, Callable, TypeVar, Type, List, Generic, Iterable, Generator, Awaitable, Optional, Tuple
+from typing import Any, Union, Callable, TypeVar, Type, List, Iterable, Generator, Awaitable, Optional, Tuple
 from .events import AbstractEventLoop
 from concurrent.futures import (
     CancelledError as CancelledError,

stdlib/3/asyncio/locks.pyi

@@ -1,4 +1,4 @@
-from typing import Any, Callable, Generator, Iterable, Iterator, List, Type, TypeVar, Union, Optional, Awaitable
+from typing import Any, Callable, Generator, List, Type, TypeVar, Union, Optional, Awaitable
 
 from .coroutines import coroutine
 from .events import AbstractEventLoop

stdlib/3/asyncio/queues.pyi

@@ -1,7 +1,5 @@
-import sys
 from asyncio.events import AbstractEventLoop
 from .coroutines import coroutine
-from .futures import Future
 from typing import Any, Generator, Generic, List, TypeVar, Optional
 
 __all__: List[str]

stdlib/3/asyncio/tasks.pyi

@@ -1,8 +1,8 @@
 import concurrent.futures
 import sys
-from typing import (Any, TypeVar, Set, Dict, List, TextIO, Union, Tuple, Generic, Callable,
-                    Coroutine, Generator, Iterable, Awaitable, overload, Sequence, Iterator,
-                    Optional)
+from typing import (
+    Any, TypeVar, Set, List, TextIO, Union, Tuple, Generic, Generator, Iterable, Awaitable, overload, Iterator, Optional,
+)
 from types import FrameType
 from .events import AbstractEventLoop
 from .futures import Future

stdlib/3/asyncio/transports.pyi

@@ -1,5 +1,5 @@
 import sys
-from typing import Dict, Any, TypeVar, Mapping, List, Optional, Tuple
+from typing import Any, Mapping, List, Optional, Tuple
 from asyncio.protocols import BaseProtocol
 
 __all__: List[str]