feat: publicize doc implemetation

one/docs/demo/region-picker/default.vue

@@ -0,0 +1,44 @@
+<template>
+<article>
+  <h4>Chinese Regions</h4>
+  <section>
+    <veui-region-picker
+      v-model="selected"
+      :datasource="region"
+    />
+  </section>
+  <section>Selected IDs: {{ result }}</section>
+</article>
+</template>
+
+<script>
+import { RegionPicker } from 'veui'
+import region from '@/common/region'
+
+export default {
+  components: {
+    'veui-region-picker': RegionPicker
+  },
+  data () {
+    return {
+      region,
+      selected: null
+    }
+  },
+  computed: {
+    result () {
+      return (this.selected || []).join(', ') || '-'
+    }
+  }
+}
+</script>
+
+<style lang="less" scoped docs>
+h4 {
+  margin-top: 0;
+}
+
+section {
+  margin-bottom: 10px;
+}
+</style>