security: add RSS feed option (#23328)

Do not merge, we need to configure some behavior rules in CloudFront

## Description
Adds an RSS feed subscription option to the security announcements page.
We can reuse this shortcode for other release notes or announcements
pages if we want!

## Related issues or tickets
https://docker.atlassian.net/browse/ENGDOCS-2939

## Reviews
- [ ] Editorial review

content/manuals/security/security-announcements.md

@@ -3,11 +3,15 @@ description: Docker security announcements
 keywords: Docker, CVEs, security, notice, Log4J 2, Log4Shell, Text4Shell, announcements
 title: Docker security announcements
 linkTitle: Security announcements
+outputs: ["HTML", "markdown", "RSS"]
+type: "security-announcements"
 weight: 80
 toc_min: 1
 toc_max: 2
 ---
 
+{{< rss-button feed="/security/security-announcements/index.xml" text="Subscribe to security RSS feed" >}}
+
 ## Docker Desktop 4.44.3 security update: CVE-2025-9074
 
 _Last updated August 20, 2025_

hugo_stats.json

@@ -200,6 +200,7 @@
       "border-divider-light",
       "border-gray-100",
       "border-gray-200",
+      "border-gray-300",
       "border-gray-400",
       "border-green-400",
       "border-l-2",
@@ -247,6 +248,7 @@
       "dark:border-b-blue-600",
       "dark:border-divider-dark",
       "dark:border-gray-400",
+      "dark:border-gray-600",
       "dark:border-gray-700",
       "dark:border-green-400",
       "dark:border-l-magenta-dark",
@@ -486,6 +488,7 @@
       "pt-4",
       "px-1",
       "px-2",
+      "px-3",
       "px-4",
       "py-0.5",
       "py-1",
@@ -504,7 +507,10 @@
       "rotate-45",
       "rounded",
       "rounded-full",
+      "rounded-md",
       "rounded-sm",
+      "rss-button",
+      "rss-subscribe",
       "scale-50",
       "scale-75",
       "scroll-mt-2",

layouts/security-announcements/single.rss.xml

@@ -0,0 +1,20 @@
+<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
+  <channel>
+    <title>Docker Docs - Security Announcements</title>
+    <link>{{ .Permalink }}</link>
+    <description>Security announcements and advisories</description>
+    <generator>Hugo -- gohugo.io</generator>
+    <language>{{ .Site.LanguageCode | default "en" }}</language>
+    <lastBuildDate>{{ now.Format "Mon, 02 Jan 2006 15:04:05 -0700" | safeHTML }}</lastBuildDate>
+    <atom:link href="{{ .Permalink }}index.xml" rel="self" type="application/rss+xml" />
+    
+    <!-- Single item with the page content -->
+    <item>
+      <title>Latest Security Announcements - {{ now.Format "January 2, 2006" }}</title>
+      <link>{{ .Permalink }}</link>
+      <pubDate>{{ now.Format "Mon, 02 Jan 2006 15:04:05 -0700" | safeHTML }}</pubDate>
+      <guid>{{ .Permalink }}#{{ now.Unix }}</guid>
+      <description>{{ .Plain | html }}</description>
+    </item>
+  </channel>
+</rss>

layouts/shortcodes/rss-button.html

@@ -0,0 +1,14 @@
+{{ $feed := .Get "feed" | default "index.xml" }}
+{{ $text := .Get "text" | default "Subscribe to RSS feed" }}
+<button
+  onclick="window.open('{{ $feed }}', '_blank')"
+  data-heap-id="rss-subscribe-button"
+  class="inline-flex items-center gap-2 border border-gray-300 dark:border-gray-600 rounded-md hover:bg-gray-50 dark:hover:bg-gray-900 py-2 px-3 text-sm transition-colors"
+>
+  <span class="icon-svg text-base leading-none">
+    {{ partial "icon" "rss_feed" }}
+  </span>
+  <div class="leading-tight">
+    <div class="text-base">{{ $text }}</div>
+  </div>
+</button>