Move GdkFullscreenMode to the right header

This enum is just used for a GdkToplevel property now,
so move the declaration to the gdktoplevel.h header.

gdk/gdksurface.h

@@ -63,20 +63,6 @@ typedef enum
   GDK_SURFACE_EDGE_SOUTH_EAST
 } GdkSurfaceEdge;
 
-/**
- * GdkFullscreenMode:
- * @GDK_FULLSCREEN_ON_CURRENT_MONITOR: Fullscreen on current monitor only.
- * @GDK_FULLSCREEN_ON_ALL_MONITORS: Span across all monitors when fullscreen.
- *
- * Indicates which monitor (in a multi-head setup) a surface should span over
- * when in fullscreen mode.
- **/
-typedef enum
-{
-  GDK_FULLSCREEN_ON_CURRENT_MONITOR,
-  GDK_FULLSCREEN_ON_ALL_MONITORS
-} GdkFullscreenMode;
-
 /**
  * GdkSurfaceState:
  * @GDK_SURFACE_STATE_WITHDRAWN: the surface is not shown

gdk/gdktoplevel.h

@@ -30,6 +30,20 @@
 
 G_BEGIN_DECLS
 
+/**
+ * GdkFullscreenMode:
+ * @GDK_FULLSCREEN_ON_CURRENT_MONITOR: Fullscreen on current monitor only.
+ * @GDK_FULLSCREEN_ON_ALL_MONITORS: Span across all monitors when fullscreen.
+ *
+ * Indicates which monitor (in a multi-head setup) a surface should span over
+ * when in fullscreen mode.
+ **/
+typedef enum
+{
+  GDK_FULLSCREEN_ON_CURRENT_MONITOR,
+  GDK_FULLSCREEN_ON_ALL_MONITORS
+} GdkFullscreenMode;
+
 #define GDK_TYPE_TOPLEVEL (gdk_toplevel_get_type ())
 
 GDK_AVAILABLE_IN_ALL