Add confirmation message when deleting the variable

Author: humitos

readthedocs/templates/projects/environmentvariable_detail.html

@@ -18,6 +18,11 @@
 {% block project_edit_content %}
   <form method="post" action="{% url 'projects_environmentvariables_delete' project_slug=project.slug environmentvariable_pk=environmentvariable.pk %}">
     {% csrf_token %}
+    <p>
+    {% blocktrans trimmed %}
+      Are you sure you want to delete the environment variable</b>?
+    {% endblocktrans %}
+    </p>
     <input type="submit" value="{% trans "Delete" %}">
   </form>
 {% endblock %}