Rework changeset descriptions to use h6 tags, and refactor changeset lists to use list-group-flush

The descriptions are probably best not as a header, but still needs to be something more prominent than surrounding text.

app/assets/stylesheets/common.scss

@@ -1108,21 +1108,12 @@ tr.turn:hover {
 
 #sidebar .changesets {
   li {
-    padding: 15px 20px;
-    border-bottom: 1px solid $grey;
     cursor: pointer;
 
     &.selected { background: $list-highlight; }
     /* color is derived from changeset bbox fillColor in history.js */
   }
 
-  h4 {
-    margin: 0;
-    a {
-      color: #000;
-    }
-  }
-
   .comments {
     float: right;
     color: $darkgrey;

app/views/browse/changeset.html.erb

@@ -6,7 +6,7 @@
 </h2>
 
 <div class="browse-section">
-  <h4><%= linkify(h(@changeset.tags["comment"].to_s.presence || t("browse.no_comment"))) %></h4>
+  <h6><%= linkify(h(@changeset.tags["comment"].to_s.presence || t("browse.no_comment"))) %></h6>
   <div class="details"><%= changeset_details(@changeset) %></div>
 
   <%= render :partial => "tag_details", :object => @changeset.tags.except("comment") %>

app/views/changesets/_changeset.html.erb

@@ -10,12 +10,12 @@
      }
    end %>
 
-<%= content_tag "li", :id => "changeset_#{changeset.id}", :data => { :changeset => changeset_data } do %>
-  <h4>
-    <a class="changeset_id" href="<%= changeset_path(changeset) %>">
+<%= content_tag "li", :id => "changeset_#{changeset.id}", :data => { :changeset => changeset_data }, :class => "list-group-item" do %>
+  <h6>
+    <a class="changeset_id text-dark" href="<%= changeset_path(changeset) %>">
       <%= changeset.tags["comment"].to_s.presence || t("browse.no_comment") %>
     </a>
-  </h4>
+  </h6>
   <div class="comments comments-<%= changeset.comments.length %>">
     <%= changeset.comments.length %>
     <span class="icon note grey"></span>

app/views/changesets/index.html.erb

@@ -1,5 +1,5 @@
 <% if @changesets.present? %>
-  <ol class="changesets">
+  <ol class="changesets list-group list-group-flush">
     <%= render @changesets %>
   </ol>
 <% if @changesets.size == 20 -%>