fix: JSONRPCDispatcher no-builder __init__ overload accepts all kwargs

The first overload (no transport_builder) was missing peer_cancel_mode and
raise_handler_exceptions, so callers couldn't pass them without also
supplying a builder. Pure typing fix; the impl already handled them.

Author: maxisbey

src/mcp/shared/jsonrpc_dispatcher.py

@@ -192,6 +192,9 @@ def __init__(
         self: JSONRPCDispatcher[TransportContext],
         read_stream: ReadStream[SessionMessage | Exception],
         write_stream: WriteStream[SessionMessage],
+        *,
+        peer_cancel_mode: PeerCancelMode = "interrupt",
+        raise_handler_exceptions: bool = False,
     ) -> None: ...
     @overload
     def __init__(