Optimize issue edit description link (#21085).

Patch by Felix Gliesche.

git-svn-id: http://svn.redmine.org/redmine/trunk@14753 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/views/issues/_form.html.erb

@@ -24,7 +24,7 @@
 <% if @issue.safe_attribute? 'description' %>
 <p>
   <%= f.label_for_field :description, :required => @issue.required_attribute?('description') %>
-  <%= link_to_function image_tag('edit.png'), '$(this).hide(); $("#issue_description_and_toolbar").show()' unless @issue.new_record? %>
+  <%= link_to_function content_tag(:span, l(:button_edit), :class => 'icon icon-edit'), '$(this).hide(); $("#issue_description_and_toolbar").show()' unless @issue.new_record? %>
   <%= content_tag 'span', :id => "issue_description_and_toolbar", :style => (@issue.new_record? ? nil : 'display:none') do %>
     <%= f.text_area :description,
                    :cols => 60,