Fix small UI text mistakes

2 small UI text mistakes in the JS section of the theme settings cause some confusion.

They mention "CSS" where they should say "JavaScript" files.

$form['js']['nuke']['stripper']['mothership_js_freeform'] = array(
         '#type'          => 'textarea',
        '#title'         => t('Path to the CSS files thats gonna be stripped '),
         '#default_value' => theme_get_setting('mothership_js_freeform'),
         '#description'   => t('The whole path to the file(s) that should be removed from
        '#suffix'       => '<strong>CSS file paths, based on the modules loaded in you D
       );