WebHost: delete unused script tag (#4062)

WebHostLib/templates/templates.html

@@ -4,9 +4,6 @@
     {% include 'header/grassHeader.html' %}
     <title>Option Templates (YAML)</title>
     <link rel="stylesheet" type="text/css" href="{{ url_for('static', filename="styles/markdown.css") }}" />
-    <script src="https://cdnjs.cloudflare.com/ajax/libs/showdown/1.9.1/showdown.min.js"
-            integrity="sha512-L03kznCrNOfVxOUovR6ESfCz9Gfny7gihUX/huVbQB9zjODtYpxaVtIaAkpetoiyV2eqWbvxMH9fiSv5enX7bw=="
-            crossorigin="anonymous"></script>
 {% endblock %}
 
 {% block body %}