fix(sort): calls next reducers complete() on completion

Author: pitchart

src/Reducer/Sort.php

@@ -45,7 +45,8 @@ public function complete($result)
                 $result = $item;
             }
         }
+        $this->store = [];
 
-        return $result;
+        return $this->next->complete($result);
     }
 }