gtkmm: New API in gtkmm 3.90

gtkmm 4.10.0

New API in gtkmm 3.90

Class Gdk::DrawContext
Member Gtk::Assistant::Assistant (bool use_header_bar)
Member Gtk::DrawingArea::set_draw_func (const SlotDraw & slot)
Member Gtk::DrawingArea::SlotDraw
Class Gtk::Snapshot
Member Gtk::TextIterBase::SlotFindChar
Member Gtk::TreeSelection::get_selected () const
Member Gtk::TreeSelection::get_selected (Glib::RefPtr< const TreeModel > & model) const