Adds the given @icon_set to the icon factory, under the name
@stock_id. @stock_id should be namespaced for your application,
e.g. “myapp-whatever-icon”. Normally applications create a
#GtkIconFactory, then add it to the list of default factories with
gtk_icon_factory_add_default(). Then they pass the @stock_id to
widgets such as #GtkImage to display the icon. Themes can provide
an icon with the same name (such as "myapp-whatever-icon") to
override your application’s default icons. If an icon already
existed in @factory for @stock_id, it is unreferenced and replaced
with the new @icon_set.
Adds the given @icon_set to the icon factory, under the name @stock_id. @stock_id should be namespaced for your application, e.g. “myapp-whatever-icon”. Normally applications create a #GtkIconFactory, then add it to the list of default factories with gtk_icon_factory_add_default(). Then they pass the @stock_id to widgets such as #GtkImage to display the icon. Themes can provide an icon with the same name (such as "myapp-whatever-icon") to override your application’s default icons. If an icon already existed in @factory for @stock_id, it is unreferenced and replaced with the new @icon_set.