Use re-exports instead of TypeAliases in email.parser (#7665)

stdlib/email/parser.pyi

@@ -1,16 +1,11 @@
-import email.feedparser
 from collections.abc import Callable
-from email import _MessageT
+from email.feedparser import BytesFeedParser as BytesFeedParser, FeedParser as FeedParser
 from email.message import Message
 from email.policy import Policy
 from typing import BinaryIO, TextIO
-from typing_extensions import TypeAlias
 
 __all__ = ["Parser", "HeaderParser", "BytesParser", "BytesHeaderParser", "FeedParser", "BytesFeedParser"]
 
-FeedParser: TypeAlias = email.feedparser.FeedParser[_MessageT]
-BytesFeedParser: TypeAlias = email.feedparser.BytesFeedParser[_MessageT]
-
 class Parser:
     def __init__(self, _class: Callable[[], Message] | None = ..., *, policy: Policy = ...) -> None: ...
     def parse(self, fp: TextIO, headersonly: bool = ...) -> Message: ...