stdlib: enforce CamelCase for type alias names (#8255)

stdlib/asynchat.pyi

@@ -9,7 +9,7 @@ class simple_producer:
 class async_chat(asyncore.dispatcher):
     ac_in_buffer_size: int
     ac_out_buffer_size: int
-    def __init__(self, sock: socket.socket | None = ..., map: asyncore._maptype | None = ...) -> None: ...
+    def __init__(self, sock: socket.socket | None = ..., map: asyncore._MapType | None = ...) -> None: ...
     @abstractmethod
     def collect_incoming_data(self, data: bytes) -> None: ...
     @abstractmethod