Remove gtk_style_context_reset_widgets

This should never be necessary to call from the outside.
Whenever we fail to update styles properly, it is a bug.

docs/reference/gtk/gtk4-sections.txt

@@ -4437,7 +4437,6 @@ gtk_style_context_get_margin
 gtk_style_context_lookup_color
 gtk_style_context_remove_provider
 gtk_style_context_remove_provider_for_display
-gtk_style_context_reset_widgets
 gtk_style_context_restore
 gtk_style_context_save
 gtk_style_context_add_class

gtk/gtksettings.c

@@ -25,7 +25,7 @@
 #include "gtkintl.h"
 #include "gtkprivate.h"
 #include "gtkscrolledwindow.h"
-#include "gtkstylecontext.h"
+#include "gtkstylecontextprivate.h"
 #include "gtkstyleproviderprivate.h"
 #include "gtktypebuiltins.h"
 #include "gtkversion.h"

gtk/gtkstylecontext.h

@@ -903,9 +903,6 @@ GDK_AVAILABLE_IN_ALL
 void gtk_style_context_get_margin           (GtkStyleContext *context,
                                              GtkBorder       *margin);
 
-GDK_AVAILABLE_IN_ALL
-void gtk_style_context_reset_widgets        (GdkDisplay      *display);
-
 GDK_AVAILABLE_IN_ALL
 void        gtk_render_insertion_cursor
                                    (GtkStyleContext     *context,

gtk/gtkstylecontextprivate.h

@@ -59,6 +59,9 @@ PangoAttrList *_gtk_style_context_get_pango_attributes       (GtkStyleContext *c
 AtkAttributeSet *_gtk_style_context_get_attributes           (AtkAttributeSet    *attributes,
                                                               GtkStyleContext    *context);
 
+GDK_AVAILABLE_IN_ALL
+void gtk_style_context_reset_widgets        (GdkDisplay      *display);
+
 G_END_DECLS
 
 #endif /* __GTK_STYLE_CONTEXT_PRIVATE_H__ */