add localization string

client/components/cards/cardCustomFields.jade

@@ -125,7 +125,7 @@ template(name="cardCustomField-stringtemplate")
         +inlinedForm(classNames="js-card-customfield-stringtemplate")
             each item in stringtemplateItems.get
                 input.js-card-customfield-stringtemplate-item(type="text" value=item placeholder="")
-            input.js-card-customfield-stringtemplate-item.last(type="text" value="" placeholder="{{_ 'custom-field-dropdown-options-placeholder'}}")
+            input.js-card-customfield-stringtemplate-item.last(type="text" value="" placeholder="{{_ 'custom-field-stringtemplate-item-placeholder'}}")
             .edit-controls.clearfix
                 button.primary(type="submit") {{_ 'save'}}
                 a.fa.fa-times-thin.js-close-inlined-form

i18n/en.i18n.json

@@ -991,5 +991,6 @@
   "moveSwimlanePopup-title": "Move Swimlane",
   "custom-field-stringtemplate": "String Template",
   "custom-field-stringtemplate-format": "Format (use %{value} as placeholder)",
-  "custom-field-stringtemplate-separator": "Separator (use   or   for a space)"
+  "custom-field-stringtemplate-separator": "Separator (use   or   for a space)",
+  "custom-field-stringtemplate-item-placeholder": "Press enter to add more items"
 }