Move from mathjax to katex

templates/chat/chat.html

@@ -5,9 +5,6 @@
 {% block title %} {{_('Chat Box')}} {% endblock %}
 {% block js_media %}
 
-  {% if REQUIRE_JAX %}
-    {% include "mathjax-load.html" %}
-  {% endif %}
   {% include "comments/math.html" %}
   <script type="text/javascript" src="{{ static('event.js') }}"></script>
   <script type="module" src="https://unpkg.com/emoji-picker-element@1"></script>

templates/chat/chat_js.html

@@ -52,7 +52,7 @@
 
   function postProcessMessages() {
     register_time($('.time-with-rel'));
-    MathJax.typeset();
+    renderKatex();
     populateCopyButton();
     merge_authors();
   }