docs: remove dead link (#561)

Florence

2023-11-01 05a1c34c6f6973eebcbcc50f50b64c2a0d62e8fa

 quartz/plugins/emitters/404.tsx

@@ -28,7 +28,10 @@
    async emit(ctx, _content, resources, emit): Promise<FilePath[]> {
      const cfg = ctx.cfg.configuration
      const slug = "404" as FullSlug
      const externalResources = pageResources(slug, resources)

      const url = new URL(`https://${cfg.baseUrl ?? "example.com"}`)
      const path = url.pathname as FullSlug
      const externalResources = pageResources(path, resources)
      const [tree, vfile] = defaultProcessedContent({
        slug,
        text: "Not Found",