add note about preview

Author: ak4t0sh

lang/en/filter_codepen.php

@@ -27,6 +27,7 @@
 defined('MOODLE_INTERNAL') || die();
 
 $string['filtername'] = 'CodePen';
+$string['preview_desc'] = 'Save your settings to see the result.';
 $string['settingformats'] = 'Apply to formats';
 $string['settingformats_desc'] = 'The filter will be applied only if the original text was inserted in one of the selected formats.';
 $string['settingheading'] = 'Information';

settings.php

@@ -64,5 +64,5 @@
     $pen = $filter->filter($pen, ['originalformat' => FORMAT_HTML]);
     $settings->add(new admin_setting_heading('filter_codepen/preview',
                 get_string('preview'),
-                $pen));
+                get_string('preview_desc', 'filter_codepen').$pen));
 }