set_use_markup
Description:
Sets whether to use Pango markup for the banner title.
See also [func@Pango.parse_markup].
Parameters:
| this | a banner | 
| use_markup | whether to use markup | 
Sets whether to use Pango markup for the banner title.
See also [func@Pango.parse_markup].
| this | a banner | 
| use_markup | whether to use markup |