我正在为一个大学项目创建一个插件。该插件非常简单：它搜索网站地址的名称，在帖子中找到后，会输出带有图像的网站地址。但是，我无法让代码正常工作。我试过这个：

<?php
/*
Plugin Name: Murtaghs Trademark Plugin
Plugin URI: http://www.MurtaghsPub&Undertakers.ie
Description: Adds Murtaghs Logo Wherever name Of Business Displayed On Page.
Author: Connell Gray
Version: 1.0
Author URI: http://www.MurtaghsPub&Undertakers.ie
*/
function Murtaghs_Trademark_Plugin($text) {

    $site_name = get_bloginfo();
    //the logo.jpg file is stored in a folder called images which i  have created in the plugins folder//
    $new_site_name = $site_name . \'<sup>echo \'<img src="\' . plugins_url( \'images/wordpress.png\' ,"logo.jpg"  ) . \'" > \'</sup>\';

    $text = str_replace($site_name,$new_site_name,$text);

    return $text;
}
add_filter(\'the_content\',\'Murtaghs_Trademark_Plugin\');

?>