message: Fixed vue warning
diff: <span class="dictcn-pron-item"
  v-if="result.prons"
  v-for="pron in result.prons"
  - >{{ pron.phsym }} <speaker v-for="au in pron.audio" :src="au"></speaker></span>
  + >{{ pron.phsym }} <speaker v-for="(au, i) in pron.audio" :src="au" :key="i"></speaker></span>
  </div>
  <div class="chart" v-if="result.chart">
  <highcharts :options="chartOpt"></highcharts>
  