views: refactor post flag and appeal reasons.

* Prefer partials over helpers.
* Add css classes to flag/appeal reason lists.
* Wrap dtext in span.prose container.

app/views/post_appeals/_reasons.html.erb

@@ -0,0 +1,15 @@
+<ul class="post-appeal-reasons">
+  <% appeals.each do |appeal| %>
+    <li class="post-appeal-reason">
+      <span class="prose"><%= format_text(appeal.reason, inline: true) %></span>
+
+      - <%= link_to_user(appeal.creator) %>
+
+      <% if CurrentUser.is_moderator? %>
+        (<%= link_to_ip(appeal.creator_ip_addr) %>)
+      <% end %>
+
+      - <%= time_ago_in_words_tagged(appeal.created_at) %>
+    </li>
+  <% end %>
+</ul>