[gtkmm] Notebook: Remove NotebookTab enum.

[Murray Cumming <murrayc src gnome org>]

commit cccd87206baec531d4e514b577a06ef23559684f
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Apr 27 21:17:03 2017 +0200

    Notebook: Remove NotebookTab enum.
    
    We don't use it in the API. It is used in the C API only in
    a keybinding signal, which we would not wrap.

 gtk/src/notebook.hg |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/gtk/src/notebook.hg b/gtk/src/notebook.hg
index ead986d..d69d383 100644
--- a/gtk/src/notebook.hg
+++ b/gtk/src/notebook.hg
@@ -29,7 +29,6 @@ namespace Gtk
 {
 
 _CC_INCLUDE(gtk/gtk.h)
-_WRAP_ENUM(NotebookTab, GtkNotebookTab)
 
 /** Container which shows one of its children at a time, in tabbed windows.
  *