code: VariableMap getStringMap() {
      ImmutableMap.Builder<String, String> map = ImmutableMap.builder();
      for (Result result : Iterables.filter(results.values(), USED_RESULTS)) {
        map.put(result.replacement, result.original);
      }
  
      VariableMap stringMap = new VariableMap(map.build());
      return stringMap;
    }
docs: Get the list of replaces as a VariableMap