code: public Mutations<S> move(int offset) {
          int[] newMutations = new int[mutations.length];
          for (int i = 0; i < mutations.length; ++i)
              newMutations[i] = Mutation.move(mutations[i], offset);
          return new Mutations<S>(alphabet, newMutations, true);
      }
docs: Moves positions of mutations by specified offset
  
  @param offset offset
  @return relocated positions