feat: add itemRender demo

fix #4786

src/layouts/BasicLayout.tsx

@@ -117,6 +117,14 @@ const BasicLayout: React.FC<BasicLayoutProps> = props => {
         },
         ...routers,
       ]}
+      itemRender={(route, params, routes, paths) => {
+        const first = routes.indexOf(route) === 0;
+        return first ? (
+          <Link to={paths.join('/')}>{route.breadcrumbName}</Link>
+        ) : (
+          <span>{route.breadcrumbName}</span>
+        );
+      }}
       footerRender={footerRender}
       menuDataRender={menuDataRender}
       formatMessage={formatMessage}