[Improvement] follow eslint-plugin-vue strongly-recommended code style (#482)

docs/demos/views/waterfall.vue

@@ -40,7 +40,7 @@ export default {
     loadMore() {
       this.disabled = true;
       setTimeout(() => {
-        for (let i = 0; i < 5; i ++) {
+        for (let i = 0; i < 5; i++) {
           this.list.push(this.list.length);
         }
         this.disabled = false;
@@ -50,7 +50,6 @@ export default {
 };
 </script>
 
-
 <style lang="postcss">
 .demo-waterfall {
   ul {