window: rename enum pointer_type to cursor_type

This avoids confusion with the pointer devices (struct wl_pointer).
diff --git a/clients/gears.c b/clients/gears.c
index ce8212a..5cfc298 100644
--- a/clients/gears.c
+++ b/clients/gears.c
@@ -243,7 +243,7 @@
 			gears->view.rotx = gears->view.rotx + 360;
 	}
 
-	return POINTER_LEFT_PTR;
+	return CURSOR_LEFT_PTR;
 }
 
 static void