fix: error TS2345:

Author: ATQQ

packages/vitepress-plugin-rss/src/node.ts

@@ -136,7 +136,7 @@ export async function genFeed(config: SiteConfig, rssOptions: RSSOptions) {
   const { baseUrl, filename } = rssOptions
 
   // eslint-disable-next-line unused-imports/no-unused-vars
-  const { renderHTML, transform = (v) => v, ...restOps } = rssOptions
+  const { renderHTML, transform = v => v, ...restOps } = rssOptions
   const feed = new Feed({
     id: rssOptions.baseUrl,
     link: rssOptions.baseUrl,
@@ -158,7 +158,7 @@ export async function genFeed(config: SiteConfig, rssOptions: RSSOptions) {
       id: link,
       link,
       description,
-      content: transform(htmlCache.get(post.filepath)?.replaceAll('​', '')),
+      content: transform((htmlCache.get(post.filepath) ?? '').replaceAll('​', '')),
       author: [
         {
           name: author,