[Feature Request] mint-swipe 能不能支持自定义显示个数

### Existing Component
是

### Component Name
mint-swipe

### Description
在vue 项目中，使用 mint-swipe来实现轮播效果，但是业务需求是显示一个半，好让用户知道这里是可以左右滑动的，但是查看api，没有这个参数，不知道是否可以扩展一下

Start by locating the mint-swipe component and its API or documentation; the issue does not name a file or test. Check how the component currently determines slide widths and visible items, then define the custom visible-count behavior, including the requested one-and-a-half-item display, and verify it with tests.

Written by the indexing model from the issue text.