Change headline for project custom fields tab

app/views/projects/form/_custom_fields.html.erb

@@ -28,7 +28,7 @@ See doc/COPYRIGHT.rdoc for more details.
 ++#%>
 
 <fieldset class="form--fieldset -with-control" id="project_issue_custom_fields">
-  <legend class="form--fieldset-legend"><%=l(:label_custom_field_plural)%></legend>
+  <legend class="form--fieldset-legend"><%=l(:label_enabled_project_custom_fields)%></legend>
   <div class="form--fieldset-control">
     <span class="form--fieldset-control-container">
       (<%= check_all_links 'project_issue_custom_fields' %>)

config/locales/en.yml

@@ -751,6 +751,7 @@ en:
   label_duplicates: "duplicates"
   label_edit: "Edit"
   label_enable_multi_select: "Toggle multiselect"
+  label_enabled_project_custom_fields: 'Enabled custom fields'
   label_end_to_end: "end to end"
   label_end_to_start: "end to start"
   label_enumeration_new: "New enumeration value"