Add enum case signature

Knowing case value can be useful

Author: adriendupuis

tools/php_api_ref/.phpdoc/template/components/enum-case-signature.html.twig

@@ -0,0 +1,8 @@
+{% set code %}{% apply spaceless %}
+    {% if node.parent.backedType %}
+        <span class="phpdocumentor-signature__type">{{ node.parent.backedType }} </span>
+    {% endif %}
+    <span class="phpdocumentor-signature__name">{{ node.name }}</span> = <span class="phpdocumentor-signature__default-value">{{ node.value | default('""') }}</span>
+{% endapply %}{% endset %}
+
+{% include 'components/signature.html.twig' with { code } %}

tools/php_api_ref/.phpdoc/template/components/enum-case.html.twig

@@ -2,6 +2,7 @@
     {% embed 'components/content-header.html.twig' with { node: case, anchor: 'enumcase_' ~ case.name, anchor_link: link(case), header_tag: 'h3' } %}
     {% endembed %}
     {% include 'components/summary.html.twig' with { node: case } %}
+    {% include 'components/enum-case-signature.html.twig' with { node: case } %}
     {% include 'components/deprecation.html.twig' with { node: case } %}
     {% include 'components/description.html.twig' with { node: case } %}
     {% include 'components/description.html.twig' with { node: case.var[0] } %}