Add a 'none' text on rendering when the custom fields is empty

close #347

Resources/views/CustomFieldsRendering/choice.html.twig

@@ -1,3 +1,4 @@
+{% if selected|length > 0 %}
 <ul class="custom_fields choice">
 {%- for choice in choices -%}
     {% if choice['slug'] in selected %}{%- set is_selected = true -%}{%- else -%}{%- set is_selected = false -%}{%- endif -%}
@@ -16,4 +17,7 @@
     </li>
     {%- endif -%}
 {%- endfor -%}
-</ul>
+</ul>
+{% else %}
+    <div class="custom_fields_choice empty">{{ 'None'|trans }}</div>
+{% endif %}

Resources/views/CustomFieldsRendering/text.html.twig

@@ -1 +1 @@
-{{ text }}
+{% if text is not empty %}{{ text }}{% else %}<span class="custom_fields_text empty">{{ 'None'|trans }}</span>{% endif %}