add legend to eline components

src/components/Charts/ELine.vue

@@ -84,6 +84,9 @@ export default {
           text: `${this.title}监控图表`,
           subtext: `单位为: ${this.description}`
         },
+        legend: {
+          data: [this.title]
+        },
         xAxis: {
           data: xAxis
         },