style: lint ci error (#19147)

simapp/app_config.go

@@ -1,3 +1,4 @@
+//nolint:unused,nolintlint // ignore unused code linting and directive `//nolint:unused // ignore unused code linting` is unused for linter "unused"
 package simapp
 
 import (

store/storage/rocksdb/iterator.go

@@ -134,8 +134,6 @@ func (itr iterator) Next() {
 	} else {
 		itr.source.Next()
 	}
-
-	return
 }
 
 func (itr *iterator) Error() error {