views: refactor atom feed links.

* Fix comment & forum feeds to include search params.
* Remove global post feeds (only include post feeds on post index).

app/views/comments/_index_by_comment.html.erb

@@ -16,5 +16,3 @@
 </div>
 
 <%= numbered_paginator(@comments) %>
-
-<% content_for(:html_header, auto_discovery_link_tag(:atom, comments_url(format: "atom"), title: "Comments")) %>

app/views/comments/_index_by_post.html.erb

@@ -1,5 +1,3 @@
-<% meta_description "See comments on #{Danbooru.config.app_name}." %>
-
 <div id="p-index-by-post">
   <% if !CurrentUser.user.is_builder? %>
     <div style="margin-bottom: 1em;">
@@ -24,5 +22,3 @@
 </div>
 
 <%= numbered_paginator(@posts) %>
-
-<% content_for(:html_header, auto_discovery_link_tag(:atom, comments_url(:atom, search: { do_not_bump_post: true }), title: "Comments")) %>

app/views/comments/index.html.erb

@@ -1,3 +1,8 @@
+<% meta_description "See comments on #{Danbooru.config.app_name}." %>
+
+<% atom_feed_tag "Comments", comments_url(:atom, search: params.fetch(:search, {}).permit!) %>
+<%= render "secondary_links" %>
+
 <div id="c-comments">
   <div id="a-index">
     <h1>Comments</h1>
@@ -11,5 +16,3 @@
     <% end %>
   </div>
 </div>
-
-<%= render "secondary_links" %>