Revert f3c617f on _includes/figure to make way for #3119

_includes/figure

@@ -1,6 +1,6 @@
 <figure class="{{ include.class }}">
   <img src="{{ include.image_path | relative_url }}"
-       alt="{% if include.alt %}{{ include.alt }}{% endif %}" />
+       alt="{% if include.alt %}{{ include.alt }}{% endif %}">
   {%- if include.caption -%}
     <figcaption>
       {{ include.caption | markdownify | remove: "<p>" | remove: "</p>" }}