theme_token_list (split theme_token_help in two)

add theme_token_list to support module development integrated with token
providen a centralized way to theme available replacements list
for example

  ...
  $token_list = token_get_list('field');
  unset($token_list['node reference']['link']); // remove html link if it doesn't makes sense
  // remove other available replacements that won't make sense in this context
  $form['node_link']['hover_title_replacements'] = array(
    '#value' => theme('token_list', $token_list),
  );

this certainly will avoid duplicated code and easier future support for other features

PS: a similar (but not the same) issue exists for D5 #163275: theme_token_help for a specific node.