Change internal function calls

Changed:
- Removed unnecessary call to `jsonSerialize()` method when directly used with `json_encode()`
- Replaced `call_user_func()` with direct calling of `$callback`

Author: mcaskill

Function.HTML-Build-Attributes.php

@@ -38,10 +38,7 @@ function html_build_attributes($attr, callable $callback = null)
                 if ($val instanceof Closure) {
                     $val = $val();
                 } elseif ($val instanceof JsonSerializable) {
-                    $val = json_encode(
-                        $val->jsonSerialize(),
-                        (JSON_UNESCAPED_SLASHES|JSON_UNESCAPED_UNICODE)
-                    );
+                    $val = json_encode($val, (JSON_UNESCAPED_SLASHES|JSON_UNESCAPED_UNICODE));
                 } elseif (is_callable([ $val, 'toArray' ])) {
                     $val = $val->toArray();
                 } elseif (is_callable([ $val, '__toString' ])) {
@@ -68,7 +65,7 @@ function html_build_attributes($attr, callable $callback = null)
             }
 
             if (is_callable($callback)) {
-                $val = call_user_func($callback, $val);
+                $val = $callback($val);
             } elseif (function_exists('esc_attr')) {
                 $val = esc_attr($val);
             } else {