Minor tweak for codeblocks with captions

Author: javiereguiluz

src/Templates/default/html/code.html.twig

@@ -1,4 +1,4 @@
-<div translate="no" data-loc="{{ loc }}" class="notranslate codeblock codeblock-length-{{ length }} {{ languages|map(language => "codeblock-#{language}")|join(' ') }}{% if custom_css_classes %} {{ custom_css_classes }}{% endif %}">
+<div translate="no" data-loc="{{ loc }}" class="notranslate codeblock codeblock-length-{{ length }} {{ languages|map(language => "codeblock-#{language}")|join(' ') }}{% if caption %} codeblock-has-caption{% endif %}{% if custom_css_classes %} {{ custom_css_classes }}{% endif %}">
     {% if caption %}
         <div class="codeblock-caption">{{ caption }}</div>
     {% endif %}

tests/fixtures/expected/blocks/code-blocks/code-caption.html

@@ -1,4 +1,4 @@
-<div translate="no" data-loc="1" class="notranslate codeblock codeblock-length-sm codeblock-php">
+<div translate="no" data-loc="1" class="notranslate codeblock codeblock-length-sm codeblock-php codeblock-has-caption">
    <div class="codeblock-caption">config/routes.php</div>
    <div class="codeblock-scroll">
        <pre class="codeblock-lines">1</pre>
@@ -13,7 +13,7 @@
    </div>
 </div>
 
-<div translate="no" data-loc="1" class="notranslate codeblock codeblock-length-sm codeblock-php hide">
+<div translate="no" data-loc="1" class="notranslate codeblock codeblock-length-sm codeblock-php codeblock-has-caption hide">
    <div class="codeblock-caption">config/routes.php</div>
    <div class="codeblock-scroll">
        <pre class="codeblock-lines">1</pre>