update build api doc

Author: lytc

docs/api/index.html

@@ -82,9 +82,9 @@ <h2>Sample</h2>
 <span class="hljs-keyword">import</span> ReactDOM <span class="hljs-keyword">from</span> <span class="hljs-string">'react-dom'</span>;
 <span class="hljs-keyword">import</span> { DndProvider } <span class="hljs-keyword">from</span> <span class="hljs-string">'react-dnd'</span>;
 <span class="hljs-keyword">import</span> HTML5Backend <span class="hljs-keyword">from</span> <span class="hljs-string">'react-dnd-html5-backend'</span>;
-<span class="hljs-keyword">import</span> { ContextProvider } <span class="hljs-keyword">from</span> <span class="hljs-string">'react-sortly'</span>;
+<span class="hljs-keyword">import</span> Sortly, { ContextProvider } <span class="hljs-keyword">from</span> <span class="hljs-string">'react-sortly'</span>;
 
-<span class="hljs-keyword">const</span> DefaultItemRenderer = <span class="hljs-function">(<span class="hljs-params">props</span>) =&gt;</span> {
+<span class="hljs-keyword">const</span> ItemRenderer = <span class="hljs-function">(<span class="hljs-params">props</span>) =&gt;</span> {
   <span class="hljs-keyword">const</span> { <span class="hljs-attr">data</span>: { name, depth }, drag, drop } = props;
   <span class="hljs-keyword">const</span> ref = React.useRef(<span class="hljs-literal">null</span>);
 
@@ -116,18 +116,16 @@ <h2>Sample</h2>
   );
 };
 
-const App = () = {
+const App = () =&gt; (
  <span class="hljs-tag">&lt;<span class="hljs-name">DndProvider</span> <span class="hljs-attr">backend</span>=<span class="hljs-string">{HTML5Backend}</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">ContextProvider</span>&gt;</span>
      <span class="hljs-tag">&lt;<span class="hljs-name">MySortableTree</span> /&gt;</span>
    <span class="hljs-tag">&lt;/<span class="hljs-name">ContextProvider</span>&gt;</span>
  <span class="hljs-tag">&lt;/<span class="hljs-name">DndProvider</span>&gt;</span>
-};
+);
 
-ReactDOM.render(
-  <span class="hljs-tag">&lt;<span class="hljs-name">App</span> /&gt;</span>,
-  document.getElementById('root')
-);</span></code></pre>
+const rootElement = document.getElementById('root');
+ReactDOM.render(<span class="hljs-tag">&lt;<span class="hljs-name">App</span> /&gt;</span>, rootElement);</span></code></pre>
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