core&ui: fix sidebar preview (#491)

Co-authored-by: panda <panda_dtdyy@outlook.com>

packages/ui-default/templates/partials/problem_description.html

@@ -1,7 +1,7 @@
 <div class="section__body typo" data-fragment-id="problem-description">
   {% if not pdoc.data.length and not pdoc.reference %}
     <blockquote class="warn">
-      <p>{{ _('No testdata at current.') }}</p>
+      <p>{{ _('No {0} at current.').format(_("testdata")) }}</p>
     </blockquote>
   {% endif %}
   {% if typeof(pdoc.config) == 'string' %}