[gtkmm-documentation] Popover example: Call set_draw_indicator() instead of set_mode()

[Kjell Ahlstedt <kjellahl src gnome org>]

commit ebec68edcf8a62ff75f56f237740f9b624969281
Author: Kjell Ahlstedt <kjell ahlstedt bredband net>
Date:   Tue Jan 31 18:54:51 2017 +0100

    Popover example: Call set_draw_indicator() instead of set_mode()
    
    Gtk::ToggleButton::set_mode() has been replaced by
    CheckButton::set_draw_indicator().

 examples/book/popover/examplewindow.cc |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/examples/book/popover/examplewindow.cc b/examples/book/popover/examplewindow.cc
index ac33317..ebd8226 100644
--- a/examples/book/popover/examplewindow.cc
+++ b/examples/book/popover/examplewindow.cc
@@ -84,9 +84,9 @@ void ExampleWindow::configure_form_buttons()
   m_toggle_form_buttons[1].set_image_from_icon_name("format-justify-center-symbolic", Gtk::ICON_SIZE_BUTTON, 
true);
   m_toggle_form_buttons[2].set_image_from_icon_name("format-justify-right-symbolic", Gtk::ICON_SIZE_BUTTON, 
true);
 
-  m_toggle_form_buttons[0].set_mode(false);
-  m_toggle_form_buttons[1].set_mode(false);
-  m_toggle_form_buttons[2].set_mode(false);
+  m_toggle_form_buttons[0].set_draw_indicator(false);
+  m_toggle_form_buttons[1].set_draw_indicator(false);
+  m_toggle_form_buttons[2].set_draw_indicator(false);
 
   m_toggle_form_buttons[1].join_group(m_toggle_form_buttons[0]);
   m_toggle_form_buttons[2].join_group(m_toggle_form_buttons[0]);