[gimp] app: in preferences dialog, add "show sample points" toggle

[Ell <ell src gnome org>]

commit a9d0643992ea6471e7b77a082fbb4e8b4036433c
Author: Ell <ell_se yahoo com>
Date:   Wed Sep 4 15:01:43 2019 +0300

    app: in preferences dialog, add "show sample points" toggle
    
    ... to the default-appearance options.  It was previously missing.

 app/dialogs/preferences-dialog.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/app/dialogs/preferences-dialog.c b/app/dialogs/preferences-dialog.c
index 0447f37a17..71a2a72b39 100644
--- a/app/dialogs/preferences-dialog.c
+++ b/app/dialogs/preferences-dialog.c
@@ -968,6 +968,9 @@ prefs_display_options_frame_add (Gimp         *gimp,
   prefs_check_button_add (object, "show-grid",
                           _("Show gri_d"),
                           GTK_BOX (checks_vbox));
+  prefs_check_button_add (object, "show-sample-points",
+                          _("Show _sample points"),
+                          GTK_BOX (checks_vbox));
 
   checks_vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 2);
   gtk_box_pack_start (GTK_BOX (hbox), checks_vbox, TRUE, TRUE, 0);