title: wordpress change the default label "Username" to artist name
body: <p>I want that in the registration form instead of writing label "Username", I shall write the label "Artist". I have referred to <a href="https://stackoverflow.com/questions/12825865/change-wordpresss-login-label-username">question</a> But can't get it to work. I have shown my registration form in frontend using plugin theme my login.</p>
  
  <p>Here is my code</p>
  
  <pre><code>if ($pagenow=='wp-login.php') { 
    add_filter( 'gettext', 'user_email_login_text', 20, 3 );
    function user_email_login_text( $translated_text, $text, $domain ) {
      if ($translated_text == 'Username') {
      $translated_text = 'Artist Name';
      }
  
      return $translated_text;
    }
  }
  </code></pre>