[totem] preferences: Remove forward declaration of non-existing function

[Bastien Nocera <hadess src gnome org>]

commit 4eb5c95456b750facdb9dfa2bfc2d135673c5935
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed May 5 19:28:24 2021 -0300

    preferences: Remove forward declaration of non-existing function
    
    checkbutton2_toggled_cb doesn't exist, nor is used in preferences.ui. Just
    remove this forward declaration.

 src/totem-preferences.c | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/src/totem-preferences.c b/src/totem-preferences.c
index cceb4b282..96a1fcdb3 100644
--- a/src/totem-preferences.c
+++ b/src/totem-preferences.c
@@ -48,7 +48,6 @@
 #define POBJ(x) gtk_builder_get_object (totem->prefs_xml, x)
 
 /* Callback functions for GtkBuilder */
-G_MODULE_EXPORT void checkbutton2_toggled_cb (GtkToggleButton *togglebutton, Totem *totem);
 G_MODULE_EXPORT void tpw_color_reset_clicked_cb (GtkButton *button, Totem *totem);
 G_MODULE_EXPORT void font_set_cb (GtkFontButton * fb, Totem * totem);
 G_MODULE_EXPORT void encoding_set_cb (GtkComboBox *cb, Totem *totem);