Update pyright (#6840)

stdlib/email/parser.pyi

@@ -1,10 +1,12 @@
 import email.feedparser
 from email.message import Message
 from email.policy import Policy
-from typing import BinaryIO, Callable, TextIO
+from typing import BinaryIO, Callable, TextIO, TypeVar
 
-FeedParser = email.feedparser.FeedParser
-BytesFeedParser = email.feedparser.BytesFeedParser
+_M = TypeVar("_M", bound=Message)
+
+FeedParser = email.feedparser.FeedParser[_M]
+BytesFeedParser = email.feedparser.BytesFeedParser[_M]
 
 class Parser:
     def __init__(self, _class: Callable[[], Message] | None = ..., *, policy: Policy = ...) -> None: ...