patch 9.0.1563: GTK3: window manager resize hints are incomplete

Problem:    GTK3: window manager resize hints are incomplete.
Solution:   Use NULL for second argument of gtk_window_set_geometry_hints().
            (Kenny Stauffer closes #11055)

src/gui_gtk_x11.c

@@ -3121,8 +3121,10 @@ update_window_manager_hints(int force_width, int force_height)
 			       |GDK_HINT_MIN_SIZE;
 	// Using gui.formwin as geometry widget doesn't work as expected
 	// with GTK+ 2 -- dunno why.  Presumably all the resizing hacks
-	// in Vim confuse GTK+.
-	gtk_window_set_geometry_hints(GTK_WINDOW(gui.mainwin), gui.mainwin,
+	// in Vim confuse GTK+.  For GTK 3 the second argument should be NULL
+	// to make the width/height inc works, despite the docs saying
+	// something else.
+	gtk_window_set_geometry_hints(GTK_WINDOW(gui.mainwin), NULL,
 				      &geometry, geometry_mask);
 	old_width       = width;
 	old_height      = height;

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1563,
 /**/
     1562,
 /**/