Rename and clear bad code

src/sync.rs

@@ -37,7 +37,7 @@ pub struct SyncState {
 }
 
 impl NavigatedPage<SyncMessage> for SyncState {
-    fn navigate(&self, message: &SyncMessage) -> Option<Page> {
+    fn navigate(&mut self, message: &SyncMessage) -> Option<Page> {
         if let Back = message
             && !self.frozen
         {