#2741: Add add_help_text to HtmlRenderer.
#2741: Add add_help_text to HtmlRenderer.

lsaffre/lino,lino-framework/lino,lsaffre/lino,lino-framework/lino,lino-framework/lino,lsaffre/lino,lsaffre/lino,lino-framework/lino,lino-framework/lino,lsaffre/lino