Attaches this to the given display.
You should not use this api
The display is used to add style information from “global” style providers, such as the display's `GtkSettings` instance.
If you are using a `GtkStyleContext` returned from [method@Gtk.Widget.get_style_context], you do not need to call this yourself.
this |
a `GtkStyleContext` |
display |
a `GdkDisplay` |