feat: publicize doc implemetation

one/docs/demo/slider/buffer.vue

@@ -0,0 +1,24 @@
+<template>
+<article>
+  <veui-slider
+    v-model="videoPlayProgress"
+    :secondary-progress="videoBufferProgress"
+  />
+</article>
+</template>
+
+<script>
+import { Slider } from 'veui'
+
+export default {
+  components: {
+    'veui-slider': Slider
+  },
+  data () {
+    return {
+      videoPlayProgress: 0.11,
+      videoBufferProgress: 0.57
+    }
+  }
+}
+</script>