[#4420] Add a message for new Retainers that Finances are for a single month.

app/views/deliverables/_finance_form.html.erb

@@ -1,5 +1,9 @@
 <% form.inputs :name => label, :class => "deliverable-finances #{fieldset_class}" do %>
 
+  <li style="display:none;" id='retainer-finances-message'>
+    <%= content_tag(:p, l(:text_retainer_monthly_message)) %>
+  </li>
+
   <li class="numeric optional">
     <%= content_tag(:label, l(:field_labor)) %>
     <table id="deliverable-labor" class="deliverable_finance_table">