echarts 中，tooltip 提示框单个数据后面加上字符

myChart3.setOption({

tooltip: {
  trigger: ‘axis‘,
  axisPointer: {
    type: ‘shadow‘,
  },
  textStyle: {
    "fontSize": 12
  },
  formatter: function(params) {
    return params[0].name + ‘<br/>‘
      + params[0].marker + params[0].seriesName + ‘：‘ + params[0].data + ‘<br>‘
      + params[1].marker + params[1].seriesName + ‘：‘ + params[1].data + ‘<br>‘
      + params[2].marker + params[2].seriesName + ‘：‘ + params[2].data + ‘<br>‘
      + params[3].marker + params[3].seriesName + ‘：‘ + params[3].data + ‘%‘;
  },
},

})