docs: fix

README.md

@@ -2,7 +2,7 @@
 
 # he-tree-react ![GitHub License](https://img.shields.io/github/license/phphe/he-tree-react) ![NPM Version](https://img.shields.io/npm/v/he-tree-react) ![GitHub Actions Workflow Status](https://img.shields.io/github/actions/workflow/status/phphe/he-tree-react/build.yml) ![NPM Type Definitions](https://img.shields.io/npm/types/he-tree-react) ![npm bundle size](https://img.shields.io/bundlephobia/minzip/he-tree-react)
 
-React draggable sortable tree component. [Document](https://he-tree-react.phphe.com), [Demo](https://he-tree-react.phphe.com/v1/examples).
+React draggable sortable tree component. [Document](https://he-tree-react.phphe.com), [demo](https://he-tree-react.phphe.com/v1/examples).
 
 React 可拖拽树组件. [文档](https://he-tree-react.phphe.com/zh), [演示](https://he-tree-react.phphe.com/zh/v1/examples).