feat(rss): configurable RSS feed URL (#1806)

* feat(rss): configurable RSS feed URL

* Update docs/features/RSS Feed.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update docs/features/RSS Feed.md

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Jacky Zhao <j.zhao2k19@gmail.com>

quartz/plugins/emitters/contentIndex.ts

@@ -25,6 +25,7 @@ interface Options {
   enableRSS: boolean
   rssLimit?: number
   rssFullHtml: boolean
+  rssSlug: string
   includeEmptyFiles: boolean
 }
 
@@ -33,6 +34,7 @@ const defaultOptions: Options = {
   enableRSS: true,
   rssLimit: 10,
   rssFullHtml: false,
+  rssSlug: "index",
   includeEmptyFiles: true,
 }
 
@@ -151,7 +153,7 @@ export const ContentIndex: QuartzEmitterPlugin<Partial<Options>> = (opts) => {
           await write({
             ctx,
             content: generateRSSFeed(cfg, linkIndex, opts.rssLimit),
-            slug: "index" as FullSlug,
+            slug: (opts?.rssSlug ?? "index") as FullSlug,
             ext: ".xml",
           }),
         )