Add RSS alternate to channel and subscription pages

src/invidious.cr

@@ -1880,6 +1880,7 @@ get "/feed/subscriptions" do |env|
     user = user.as(User)
     sid = sid.as(String)
     preferences = user.preferences
+    token = user.token
 
     if preferences.unseen_only
       env.set "show_watched", true

src/invidious/views/channel.ecr

@@ -1,5 +1,6 @@
 <% content_for "header" do %>
 <title><%= author %> - Invidious</title>
+<link rel="alternate" type="application/rss+xml" title="RSS" href="/feed/channel/<%= ucid %>" />
 <% end %>
 
 <div class="pure-g h-box">

src/invidious/views/subscriptions.ecr

@@ -1,5 +1,6 @@
 <% content_for "header" do %>
 <title><%= translate(locale, "Subscriptions") %> - Invidious</title>
+<link rel="alternate" type="application/rss+xml" title="RSS" href="/feed/private?token=<%= token %>" />
 <% end %>
 
 <%= rendered "components/feed_menu" %>
@@ -17,7 +18,7 @@
     </div>
     <div class="pure-u-1-3" style="text-align:right;">
         <h3>
-            <a href="/feed/private?token=<%= user.token %>"><i class="icon ion-logo-rss"></i></a>
+            <a href="/feed/private?token=<%= token %>"><i class="icon ion-logo-rss"></i></a>
         </h3>
     </div>
 </div>