feat: publicize doc implemetation

one/docs/demo/dropdown/inline.vue

@@ -0,0 +1,70 @@
+<template>
+<veui-dropdown
+  label="Files"
+  @click="alert"
+>
+  <veui-option-group>
+    <veui-option
+      value="new-file"
+      label="New File"
+    />
+    <veui-option
+      value="new-window"
+      label="New Window"
+    />
+  </veui-option-group>
+  <veui-option-group>
+    <veui-option
+      value="open"
+      label="Open…"
+    />
+    <veui-option
+      value="open-workspace"
+      label="Open Workspace…"
+    />
+    <veui-option-group
+      label="Open Recent"
+      position="popup"
+    >
+      <veui-option-group>
+        <veui-option
+          value="reopen"
+          label="Reopen Closed Editor"
+        />
+      </veui-option-group>
+      <veui-option-group>
+        <veui-option
+          value="open:~/Dropdown.vue"
+          label="~/Dropdown.vue"
+        />
+        <veui-option
+          value="open:~/Select.vue"
+          label="~/Select.vue"
+        />
+      </veui-option-group>
+    </veui-option-group>
+  </veui-option-group>
+</veui-dropdown>
+</template>
+
+<script>
+import { Dropdown, OptionGroup, Option } from 'veui'
+import toast from 'veui/managers/toast'
+
+export default {
+  components: {
+    'veui-dropdown': Dropdown,
+    'veui-option-group': OptionGroup,
+    'veui-option': Option
+  },
+  methods: {
+    alert (e) {
+      toast.info(e)
+    }
+  }
+}
+</script>
+
+<docs>
+将 `OptionGroup` 的 `position` 属性设置为 `popup` 后可以让子选项在新的浮动子菜单中展现。
+</docs>