make PartialMessageError public

Author: jxs

protocols/gossipsub/src/lib.rs

@@ -121,7 +121,9 @@ pub use metrics::Config as MetricsConfig;
 pub use self::{
     behaviour::{Behaviour, Event, MessageAuthenticity},
     config::{Config, ConfigBuilder, ValidationMode, Version},
-    error::{ConfigBuilderError, PublishError, SubscriptionError, ValidationError},
+    error::{
+        ConfigBuilderError, PartialMessageError, PublishError, SubscriptionError, ValidationError,
+    },
     partial::Partial,
     peer_score::{
         score_parameter_decay, score_parameter_decay_with_base, PeerScoreParams,