[gtk] spinbutton: Don't use gfloat in a code sample

[Timm Bäder <baedert src gnome org>]

commit e0a1311e5b0c7f0456934c14902d0b622766bfc7
Author: Timm Bäder <mail baedert org>
Date:   Wed Sep 26 09:36:31 2018 +0200

    spinbutton: Don't use gfloat in a code sample

 gtk/gtkspinbutton.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkspinbutton.c b/gtk/gtkspinbutton.c
index 9a112ebf7d..08bc849f38 100644
--- a/gtk/gtkspinbutton.c
+++ b/gtk/gtkspinbutton.c
@@ -155,7 +155,7 @@
  * // Provides a function to retrieve a floating point value from a
  * // GtkSpinButton, and creates a high precision spin button.
  *
- * gfloat
+ * float
  * grab_float_value (GtkSpinButton *button,
  *                   gpointer       user_data)
  * {