Updated the all templates to append .html in the end

_layouts/templates.html

@@ -14,7 +14,7 @@ layout: default
     {%- for template in site.templates -%}
     <article class="library-item">
       <h2 class="library-rule-name">
-        <a href="{{ template.url }}"><img src="{{ template.rule.icon }}">
+        <a href="{{ template.url }}.html"><img src="{{ template.rule.icon }}">
           {{ template.rule.name }}  
         </a>
       </h2>