Review comments taken into account

Author: sfauvel

mithril-aggregator/src/http_server/routes/reply.rs

@@ -14,6 +14,7 @@ pub struct MithrilStatusCode();
 
 impl MithrilStatusCode {
     pub fn registration_round_not_yet_opened() -> StatusCode {
+        // The unwrap is safe here because `from_16` function return error only for values outside of the range 100-999,
         StatusCode::from_u16(550).unwrap()
     }
 }

mithril-signer/src/runtime/state_machine.rs

@@ -318,7 +318,7 @@ impl StateMachine {
                 nested_error: Some(e),
             })?;
 
-        fn filter_error(
+        fn handle_registration_result(
             register_result: Result<(), Error>,
             epoch: Epoch,
         ) -> Result<Option<SignerState>, RuntimeError> {
@@ -338,7 +338,7 @@ impl StateMachine {
         }
 
         let register_result = self.runner.register_signer_to_aggregator().await;
-        let next_state_found = filter_error(register_result, epoch)?;
+        let next_state_found = handle_registration_result(register_result, epoch)?;
 
         self.metrics_service
             .get_signer_registration_success_since_startup_counter()