fix[docs]: FileCheckbox export error

packages/docs/docs/components/FileCheckbox/index.md

@@ -66,7 +66,7 @@ const FILES = [
   },
 ];
 
-export default () => {
+const Demo = () => {
   const formRef = useRef<FormInstance>(null);
   const dageFileCheckboxRef = useRef<DageFileCheckboxMethods>(null);
   const fileList = useRef<DageFileResponseType[]>([]);
@@ -136,6 +136,8 @@ export default () => {
     </DageUploadProvider>
   );
 };
+
+export default Demo;
 ```
 
 ### 禁用
@@ -170,7 +172,7 @@ const FILES = [
   },
 ];
 
-export default () => {
+const Demo = () => {
   const dageFileCheckboxRef = useRef<DageFileCheckboxMethods>(null);
 
   useEffect(() => {
@@ -195,6 +197,8 @@ export default () => {
     />
   );
 };
+
+export default Demo;
 ```
 
 ## API