daemon: clarify limitations of restricted ZMQ RPC in help text

(cherry picked from commit 0b7c34520c0d218021b7941ebbc2faf0e2b58c2f)

src/daemon/command_line_args.h

@@ -138,7 +138,7 @@ namespace daemon_args
 
   const command_line::arg_descriptor<bool> arg_restricted_zmq_rpc = {
     "restricted-zmq-rpc"
-  , "Restrict ZMQ RPC to view-only / non-sensitive methods"
+  , "Restrict ZMQ RPC by disabling some sensitive methods; does not guarantee filtering of sensitive data"
   , false
   };