comments: adjust link to howto:comment.

Replace the giant banner about reading the comment guidelines with a
smaller link to howto:comment beneath the comment text box.

app/helpers/application_helper.rb

@@ -227,6 +227,7 @@ module ApplicationHelper
     options[:value] ||= instance_variable_get("@#{object}").try(name)
     options[:preview_id] ||= "dtext-preview"
     options[:classes] ||= ""
+    options[:hint] ||= ""
     options[:type] ||= "text"
 
     render "dtext/form", options

app/views/comments/_form.html.erb

@@ -4,7 +4,7 @@
   <% if comment.new_record? %>
     <%= f.hidden_field :post_id %>
   <% end %>
-  <%= dtext_field "comment", "body", :classes => "autocomplete-mentions", :value => comment.body, :input_id => "comment_body_for_#{comment.id}", :preview_id => "dtext-preview-for-#{comment.id}" %>
+  <%= dtext_field "comment", "body", classes: "autocomplete-mentions", value: comment.body, input_id: "comment_body_for_#{comment.id}", preview_id: "dtext-preview-for-#{comment.id}", hint: link_to_wiki("Comment rules", "howto:comment").html_safe %>
   <%= f.button :submit, "Submit" %>
   <%= dtext_preview_button "comment", "body", :input_id => "comment_body_for_#{comment.id}", :preview_id => "dtext-preview-for-#{comment.id}" %>
   <% if comment.new_record? %>

app/views/comments/_index_by_post.html.erb

@@ -1,10 +1,4 @@
 <div id="p-index-by-post">
-  <% if !CurrentUser.user.is_builder? %>
-    <div style="margin-bottom: 1em;">
-      <h2>Before commenting, read the <%= link_to_wiki "how to comment guide", "howto:comment" %>.</h2>
-    </div>
-  <% end %>
-
   <% if @posts.blank? %>
     <%= render "post_sets/blank" %>
   <% end %>

app/views/dtext/_form.html.erb

@@ -10,5 +10,10 @@
     <% end %>
     <div id="<%= preview_id %>" class="dtext-preview prose"></div>
   </div>
-  <span class="hint"><%= link_to "Formatting help", dtext_help_path, remote: true, method: :get %>.</span>
+  <span class="hint">
+    <%= link_to "Formatting help", dtext_help_path, remote: true, method: :get %>.
+    <% if hint.present? %>
+      <%= hint %>.
+    <% end %>
+  </span>
 </div>

app/views/posts/show.html.erb

@@ -120,9 +120,6 @@
   <% end %>
 
   <section id="comments">
-    <% if !CurrentUser.user.is_builder? %>
-      <h2>Before commenting, read the <%= link_to_wiki "how to comment guide", "howto:comment" %>.</h2>
-    <% end %>
     <%= render "comments/partials/index/list", comments: @comments, post: @post, page: :post %>
   </section>