render_icon
Description:
Renders an icon of given size.
The base of the icon is set by the last call to one of:
- [method@MarkAttributes.set_pixbuf]
 - [method@MarkAttributes.set_gicon]
 - [method@MarkAttributes.set_icon_name]
 
size cannot be lower than 1.
Parameters:
| this | |
| widget | 
           widget of which style settings may be used.  | 
      
| size | 
           size of the rendered icon.  | 
      
Returns:
| 
           A Paintable. The paintable belongs to this and should not be unreffed.  |