Display: revert some of 38e649a changes as they generate incompatibilities with WCAG AAA

Author: ywarnier

main/template/default/announcement/view.tpl

@@ -1,5 +1,5 @@
 <div class="page-header">
-    <h3>{{ "SystemAnnouncements" | get_lang }}</h3>
+    <h4>{{ "SystemAnnouncements" | get_lang }}</h4>
 </div>
 
 {% if not announcement is empty %}

main/template/default/layout/hot_courses.tpl

@@ -1,7 +1,7 @@
 {% if hot_courses is not null and hot_courses is not empty %}
 <section class="hot-courses">
     <div class="page-header">
-        <h3>
+        <h4>
             {{ "HottestCourses"|get_lang}}
             {% if _u.is_admin %}
             <span class="pull-right">
@@ -12,7 +12,7 @@
                 </a>
             </span>
             {% endif %}
-        </h3>
+        </h4>
     </div>
     <div id="list-hot-courses" class="grid-courses">
         <div class="row">

main/template/default/session/sessions_current.tpl

@@ -1,9 +1,9 @@
 {% if hot_sessions %}
 <section id="sessions-current" class="grid-courses">
     <div class="page-header">
-        <h3>
+        <h4>
             {{ "HottestSessions"|get_lang}}
-        </h3>
+        </h4>
     </div>
     <div class="row">
         {% for session in hot_sessions %}