Add RSS autodiscovery tag

.RSSLink uses the RSS URL for the given context: the site feed for the home page, the tag feed for tag pages, no URL given for single pages.
7 years ago · 7c3134ca08
--- a/layouts/partials/header.html
+++ b/layouts/partials/header.html
@@ -6,6 +6,8 @@
    {{ "<!-- Tumble theme for Hugo: https://github.com/adrianshort/tumble -->" | safeHTML }}
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="{{ relURL "/css/main.css" }}">
    <link rel="alternate" type="application/rss+xml" title="{{ .Site.Title }}"
      href="{{ .RSSLink }}">
  </head>
  <body>
    <h1 id="site-title"><a href="{{ relURL "/" }}">{{ .Site.Title }}</a></h1>