Hide "View Markdown" when user can edit the post

If a user can edit a post, they don't need the ability to view the
markdown separately, so the button doesn't need to be shown in those
cases. I'm not sure if this should be a separate permission defined
inside the ACL or not.

tildes/tildes/templates/macros/comments.jinja2

@@ -202,6 +202,8 @@
           </li>
         {% endif %}
 
+        {# Don't show the "View Markdown" button (or dropdown) if the user can edit #}
+        {% if not request.has_permission("edit", comment) %}
         <li>
           <div class="dropdown dropdown-right">
             <button class="btn-post-action dropdown-toggle">
@@ -222,6 +224,7 @@
             </menu>
           </div>
         </li>
+        {% endif %}
       </menu>
       <div class="btn-post-settings"></div>
     {% endif %}

tildes/tildes/templates/topic.jinja2

@@ -173,7 +173,11 @@
       {{ post_action_toggle_button("remove", topic, topic.is_removed) }}
     {% endif %}
 
-    {% if topic.is_text_type and request.has_permission("view_content", topic) %}
+    {# Only show "View Markdown" (and dropdown) when it's a text topic and the user is
+       allowed to view the content, but can't edit it #}
+    {% if topic.is_text_type
+        and request.has_permission("view_content", topic)
+        and not request.has_permission("edit", topic) %}
       <li>
         <div class="dropdown dropdown-right">
           <button class="btn-post-action dropdown-toggle">