✨ added content xml shortcut

Author: mychidarko

src/Headers.php

@@ -110,6 +110,14 @@ public static function contentHtml($code = 200): void
         self::set("Content-Type", "text/html", true, $code ?? self::$httpCode);
     }
 
+    /**
+     * Set the content-type to xml
+     */
+    public static function contentXml($code = 200): void
+    {
+        self::set("Content-Type", "application/xml", true, $code ?? self::$httpCode);
+    }
+
     /**
      * Set the content-type to json
      */