Page callback: Prints a page listing a glossary of Drupal terminology.
function help_main() {
// Add CSS.
drupal_add_css(drupal_get_path('module', 'help') . '/help.css');
$output = '<h2>' . t('Help topics') . '</h2><p>' . t('Help is available on the following items:') . '</p>' . help_links_as_list();
return $output;
}