feat(Style): add multi-line ellipsis classes (#4690)

src/style/demo/index.vue

@@ -1,7 +1,8 @@
 <template>
   <demo-section>
     <demo-block :title="$t('ellipsis')">
-      <div class="van-ellipsis">{{ $t('text') }}</div>
+      <div class="van-ellipsis">{{ $t('text1') }}</div>
+      <div class="van-multi-ellipsis--l2">{{ $t('text2') }}</div>
     </demo-block>
 
     <demo-block :title="$t('hairline')">
@@ -53,14 +54,16 @@ export default {
       ellipsis: '文字省略',
       animation: '动画',
       toggle: '切换动画',
-      text: '这是一段宽度限制 250px 的文字，后面的内容会省略'
+      text1: '这是一段最多显示一行的文字，后面的内容会省略',
+      text2: '这是一段最多显示两行的文字，后面的内容会省略。这是一段最多显示两行的文字，后面的内容会省略'
     },
     'en-US': {
       hairline: 'Hairline',
       ellipsis: 'Text Ellipsis',
       animation: 'Animation',
       toggle: 'Switch animation',
-      text: 'This is a paragraph of 250px width limit, the back will be omitted.'
+      text1: 'This is a paragraph that displays up to one line of text, and the rest of the text will be omitted.',
+      text2: 'This is a paragraph that displays up to two lines of text, and the rest of the text will be omitted.'
     }
   },
 
@@ -88,10 +91,16 @@ export default {
 @import '../../style/var';
 
 .demo-style {
-  .van-ellipsis {
-    max-width: 250px;
+  .van-ellipsis,
+  .van-multi-ellipsis--l2 {
+    max-width: 300px;
     margin-left: @padding-md;
-    font-size: 13px;
+    font-size: 14px;
+    line-height: 18px;
+  }
+
+  .van-ellipsis {
+    margin-bottom: @padding-md;
   }
 
   .van-hairline--top {