Remove a bunch of unused imports (#3323)

stdlib/3/email/__init__.pyi

@@ -1,7 +1,6 @@
 # Stubs for email (Python 3.4)
 
-from typing import Callable, Optional, IO
-import sys
+from typing import Callable, IO
 from email.message import Message
 from email.policy import Policy
 

stdlib/3/email/feedparser.pyi

@@ -1,7 +1,6 @@
 # Stubs for email.feedparser (Python 3.4)
 
 from typing import Callable
-import sys
 from email.message import Message
 from email.policy import Policy
 

stdlib/3/email/message.pyi

@@ -3,7 +3,6 @@
 from typing import (
     List, Optional, Union, Tuple, TypeVar, Generator, Sequence, Iterator, Any
 )
-import sys
 from email.charset import Charset
 from email.errors import MessageDefect
 from email.header import Header

stdlib/3/email/parser.pyi

@@ -3,7 +3,7 @@
 import email.feedparser
 from email.message import Message
 from email.policy import Policy
-from typing import BinaryIO, Callable, Optional, TextIO
+from typing import BinaryIO, Callable, TextIO
 
 FeedParser = email.feedparser.FeedParser
 BytesFeedParser = email.feedparser.BytesFeedParser

stdlib/3/email/policy.pyi

@@ -2,7 +2,6 @@
 
 from abc import abstractmethod
 from typing import Any, List, Optional, Tuple, Union, Callable
-import sys
 from email.message import Message
 from email.errors import MessageDefect
 from email.header import Header