Rename templates to get syntax highlighting

src/factories/TemplateProviderFactory.kt

@@ -4,7 +4,13 @@ import com.soywiz.korte.TemplateProvider
 
 class ResourceTemplateProvider : TemplateProvider {
     override suspend fun get(template: String): String? {
-        val resource = "/templates/$template"
+
+        val tmp = when {
+            template.endsWith(".html") -> template.substringBefore(".html")
+            else -> template
+        }
+
+        val resource = "/templates/${tmp}.twig"
         return this.javaClass.getResource(resource)?.readText()
     }
 }