feat: publicize doc implemetation

one/docs/demo/input/size.vue

@@ -0,0 +1,39 @@
+<template>
+<article>
+  <p>
+    <veui-input
+      ui="l"
+      value="Large"
+    />
+  </p>
+  <p><veui-input value="Normal"/></p>
+  <p>
+    <veui-input
+      ui="s"
+      value="Small"
+    />
+  </p>
+  <p>
+    <veui-input
+      ui="xs"
+      value="Extra small"
+    />
+  </p>
+</article>
+</template>
+
+<script>
+import { Input } from 'veui'
+
+export default {
+  components: {
+    'veui-input': Input
+  }
+}
+</script>
+
+<style lang="less" scoped docs>
+p {
+  margin-bottom: 1em;
+}
+</style>