[gimp] Fix #6540 annotations on BrushSelectButton.get_brush()

[Jehan <jehanp src gnome org>]

commit f59feba61147d1a89d18b4b2d6f63f0be018c245
Author: lloyd konneker <konnekerl gmail com>
Date:   Fri Mar 5 09:34:10 2021 -0500

    Fix #6540 annotations on BrushSelectButton.get_brush()

 libgimp/gimpbrushselectbutton.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/libgimp/gimpbrushselectbutton.c b/libgimp/gimpbrushselectbutton.c
index eaf6e9030b..e393468917 100644
--- a/libgimp/gimpbrushselectbutton.c
+++ b/libgimp/gimpbrushselectbutton.c
@@ -346,10 +346,10 @@ gimp_brush_select_button_new (const gchar   *title,
 
 /**
  * gimp_brush_select_button_get_brush:
- * @button: A #GimpBrushSelectButton
- * @opacity: Opacity of the selected brush.
- * @spacing: Spacing of the selected brush.
- * @paint_mode: Paint mode of the selected brush.
+ * @button:                        A #GimpBrushSelectButton
+ * @opacity:    (out) (optional):  Opacity of the selected brush.
+ * @spacing:    (out) (optional):  Spacing of the selected brush.
+ * @paint_mode: (out) (optional):  Paint mode of the selected brush.
  *
  * Retrieves the properties of currently selected brush.
  *