[Improvement] Cell: add center prop (#771)

docs/markdown/en-US/cell.md

@@ -74,10 +74,11 @@ Vue.use(Cell).use(CellGroup);
 | title | Title | `String` | - | - |
 | value | Right text | `String` | - | - |
 | label | Description below the title | `String` | - | - |
+| border | Whether to show inner border | `Boolean` | `true` | - |
+| center | Whether to center content vertically | `Boolean` | `true` | - |
 | url | Link | `String` | - | - |
 | to | Target route of the link, same as to of `vue-router` | `String | Object` | - | - |
 | replace | If true, the navigation will not leave a history record | `String` | `false` | - |
-| border | Whether to show inner border | `Boolean` | `true` | - |
 | clickable | Whether to show click feedback when clicked | `Boolean` | `false` | - |
 | is-link | Whether to show link icon | `Boolean` | `false` | - |
 | required | Whether to show required mark | `Boolean` | `false` | - |

docs/markdown/zh-CN/cell.md

@@ -81,13 +81,14 @@ Vue.use(Cell).use(CellGroup);
 | title | 左侧标题 | `String` | - | - |
 | value | 右侧内容 | `String` | - | - |
 | label | 标题下方的描述信息 | `String` | - | - |
+| border | 是否显示内边框 | `Boolean` | `true` | - |
+| center | 是否使内容垂直居中 | `Boolean` | `false` | - |
 | url | 跳转链接 | `String` | - | - |
 | to | 路由跳转对象，同 `vue-router` 的 to | `String | Object` | - | - |
 | replace | 跳转时是否替换当前 history | `String` | `false` | - |
-| border | 是否显示内边框 | `Boolean` | `true` | - |
 | clickable | 是否开启点击反馈 | `Boolean` | `false` | - |
 | is-link | 是否展示右侧箭头并开启点击反馈 | `Boolean` | `false` | - |
-| required | 是否显示表单必填符号 | `Boolean` | `false` | - |
+| required | 是否显示表单必填星号 | `Boolean` | `false` | - |
 
 ### Cell Event