Sets markup as the contents of the tooltip, which is marked up with the [Pango text markup language]PangoMarkupFormat.
This function will take care of setting #GtkWidget:has-tooltip to true and of the default handler for the #GtkWidget::query-tooltip signal.
See also the #GtkWidget:tooltip-markup property and gtk.tooltip.Tooltip.setMarkup.
the contents of the tooltip for widget, or null
Sets markup as the contents of the tooltip, which is marked up with the [Pango text markup language]PangoMarkupFormat.
This function will take care of setting #GtkWidget:has-tooltip to true and of the default handler for the #GtkWidget::query-tooltip signal.
See also the #GtkWidget:tooltip-markup property and gtk.tooltip.Tooltip.setMarkup.