$form['cache']['contexts']['#description'].=' '.t('This block is <em>always</em> varied by the following contexts: %required-context-list.',array('%required-context-list'=>$required_context_list));
$form['cache']['contexts']['#description'].=' '.$this->t('This block is <em>always</em> varied by the following contexts: %required-context-list.',array('%required-context-list'=>$required_context_list));
}
// Add plugin-specific settings for this block type.
'#description'=>t("If <em>Show block on all pages</em> is selected, the block will contain the automatically generated menus for all of the site's books. If <em>Show block only on book pages</em> is selected, the block will contain only the one menu corresponding to the current page's book. In this case, if the current page is not in a book, no block will be displayed. The <em>Page specific visibility settings</em> or other visibility settings can be used in addition to selectively display this block."),
'#description'=>$this->t("If <em>Show block on all pages</em> is selected, the block will contain the automatically generated menus for all of the site's books. If <em>Show block only on book pages</em> is selected, the block will contain only the one menu corresponding to the current page's book. In this case, if the current page is not in a book, no block will be displayed. The <em>Page specific visibility settings</em> or other visibility settings can be used in addition to selectively display this block."),