Add typedDict for RPC messages

Currently not fully functional.

freqtrade/rpc/api_server/webserver.py

@@ -1,6 +1,6 @@
 import logging
 from ipaddress import IPv4Address
-from typing import Any, Dict, Optional
+from typing import Any, Optional
 
 import orjson
 import uvicorn
@@ -13,6 +13,7 @@ from freqtrade.exceptions import OperationalException
 from freqtrade.rpc.api_server.uvicorn_threaded import UvicornServer
 from freqtrade.rpc.api_server.ws.message_stream import MessageStream
 from freqtrade.rpc.rpc import RPC, RPCException, RPCHandler
+from freqtrade.rpc.rpc_types import RPCSendMsg
 
 
 logger = logging.getLogger(__name__)
@@ -108,7 +109,7 @@ class ApiServer(RPCHandler):
         cls._has_rpc = False
         cls._rpc = None
 
-    def send_msg(self, msg: Dict[str, Any]) -> None:
+    def send_msg(self, msg: RPCSendMsg) -> None:
         """
         Publish the message to the message stream
         """