echarts 百分号%

参考：https://blog.csdn.net/qq_32848943/article/details/119750677

tooltip: {
             trigger: 'item',
             formatter:'{c}%'　　
     },

或

        yAxis: {
          axisLabel: {
            color: "#ccc",
            formatter: function (i) {
              return i * 100 + "%";
            },
          },