修改课程下，课件名称，显示尽可能全

app/views/files/_resource_detail.html.erb

@@ -8,11 +8,11 @@
       <div class="homepagePostTitle break_word">
         <%# 如果有历史版本则提供历史版本下载 %>
         <% if file.attachment_histories.count == 0 %>
-            <%= link_to truncate(file.filename,length: 70, omission: '...'),
+            <%= link_to truncate(file.filename,length: 40, omission: '...'),
                       download_named_attachment_path(file.id, file.filename),
                       :title => file.filename+"\n"+file.description.to_s, :style => "overflow: hidden; white-space: nowrap;text-overflow: ellipsis;",:class => "linkGrey3 f_14"  %>
         <% else %>
-            <%= link_to truncate(file.filename,length: 70, omission: '...'), attachment_history_download_path(file.id),
+            <%= link_to truncate(file.filename,length: 40, omission: '...'), attachment_history_download_path(file.id),
                       :title => file.filename+"\n"+file.description.to_s,
                       :class => "linkGrey3 f_14",
                       :style => "overflow: hidden; white-space: nowrap;text-overflow: ellipsis;", :remote=>true %>