fix(templates/nav_top): fix syntax error on an empty <span>

was <span... />; is now <span...></span>

discuss_data/templates/landingpage/nav_top_landing_page.html

@@ -4,7 +4,7 @@
     <a class="navbar-brand px-3" href="{% url 'core.landing_page' %}"><img class="navbar-logo" src="{% static 'images/logo-primary-inverted.svg' %}" /></a>
 
     <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
-        <span class="navbar-toggler-icon" />
+        <span class="navbar-toggler-icon"></span>
     </button>
 
     <div class="collapse navbar-collapse" id="navbarSupportedContent">

discuss_data/templates/nav-top.html

@@ -4,7 +4,7 @@
     <a class="navbar-brand px-3" href="{% url 'core.landing_page' %}"><img class="navbar-logo" src="{% static 'images/logo-primary.svg' %}" /></a>
 
     <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
-        <span class="navbar-toggler-icon" />
+        <span class="navbar-toggler-icon"></span>
     </button>
 
     <div class="collapse navbar-collapse" id="navbarSupportedContent">