chore(createSelectorQuery): 调整变量名

pages/API/create-selector-query/create-selector-query.uvue

@@ -81,9 +81,9 @@
       }
     },
     onReady() {
-      const instance = (this.$refs['multi-child'] as ComponentPublicInstance)
-      this.selectCount = instance.$data['selectCount'] as Number
-      this.selectAllCount = instance.$data['selectAllCount'] as Number
+      const instance2 = (this.$refs['multi-child'] as ComponentPublicInstance)
+      this.selectCount = instance2.$data['selectCount'] as Number
+      this.selectAllCount = instance2.$data['selectAllCount'] as Number
       console.log('selectCount', selectCount, selectAllCount)
     },
     onResize() {