[gimp] libgimpwidgets: fix docs for GimpBusyBox:message

[Michael Natterer <mitch src gnome org>]

commit fe75ef28ad6894cf9d5b16a6c76d9aff4a64f5b6
Author: Michael Natterer <mitch gimp org>
Date:   Thu Jul 25 10:24:30 2019 +0200

    libgimpwidgets: fix docs for GimpBusyBox:message

 libgimpwidgets/gimpbusybox.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/libgimpwidgets/gimpbusybox.c b/libgimpwidgets/gimpbusybox.c
index 7332efb856..a6dfaddd66 100644
--- a/libgimpwidgets/gimpbusybox.c
+++ b/libgimpwidgets/gimpbusybox.c
@@ -90,7 +90,8 @@ gimp_busy_box_class_init (GimpBusyBoxClass *klass)
    **/
   g_object_class_install_property (object_class, PROP_MESSAGE,
                                    g_param_spec_string ("message",
-                                                        NULL, NULL,
+                                                        "Message",
+                                                        "The message to display",
                                                         NULL,
                                                         GIMP_PARAM_READWRITE |
                                                         G_PARAM_CONSTRUCT));