[data][CachedDataSource] Fixed socket type in documentation

beat/backend/python/data.py

@@ -638,7 +638,7 @@ class RemoteDataSource(DataSource):
 
         Parameters:
 
-          socket (socket): The socket to use to access the data.
+          socket (zmq.Socket): The socket to use to access the data.
 
           input_name (str): Name of the input corresponding to the data source.