update state.rs comment

src/bin/messenger/state.rs

@@ -1,6 +1,6 @@
 // The state machine used to represent one end of a conversation.
 // This includes inducing transitions and actions taken during transitions,
-// so a lot of the messenger network code is here.
+// so messages are constructed and passed to other threads from here.
 
 use mgen::{log, MessageHeader, SerializedMessage};
 use rand_distr::Distribution;