Fix duplicate labels on form inputs

It’s invalid HTML to have multiple labels nested within each other. This
was happening by accident because WTForms tries to be clever – when you
put `{{ field.label }}` in a template it prints a `<label>` tag for you,
not just the text of the label. But we put our own `<label>` tags in the
HTML to have more control of them.

This commit stops WTForms being so clever.

app/templates/components/list-entry.html

@@ -11,7 +11,7 @@
     <fieldset class="form-group{% if field.errors %} error{% endif %}" id="{{ field.name }}">
       <legend>
         <span class="form-label">
-          {{ field.label }}
+          {{ field.label.text }}
           {% if hint %}
             <span class="form-hint">
               {{ hint }}