Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stdlib/email/feedparser.pyi

@@ -0,0 +1,21 @@
+from email.message import Message
+from email.policy import Policy
+from typing import Callable, Generic, TypeVar, overload
+
+_M = TypeVar("_M", bound=Message)
+
+class FeedParser(Generic[_M]):
+    @overload
+    def __init__(self: FeedParser[Message], _factory: None = ..., *, policy: Policy = ...) -> None: ...
+    @overload
+    def __init__(self, _factory: Callable[[], _M], *, policy: Policy = ...) -> None: ...
+    def feed(self, data: str) -> None: ...
+    def close(self) -> _M: ...
+
+class BytesFeedParser(Generic[_M]):
+    @overload
+    def __init__(self: BytesFeedParser[Message], _factory: None = ..., *, policy: Policy = ...) -> None: ...
+    @overload
+    def __init__(self, _factory: Callable[[], _M], *, policy: Policy = ...) -> None: ...
+    def feed(self, data: bytes) -> None: ...
+    def close(self) -> _M: ...