[gtksourceview] completion: update copyright

[Christian Hergert <chergert src gnome org>]

commit 92d94459015f86660b7e87be3956e839560eafa7
Author: Christian Hergert <chergert redhat com>
Date:   Mon Jan 4 10:47:15 2021 -0800

    completion: update copyright
    
    While this was a greenfield rewrite, we should include people who
    contributed to the previous implementation.

 gtksourceview/gtksourcecompletion.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gtksourceview/gtksourcecompletion.c b/gtksourceview/gtksourcecompletion.c
index 917679aa..ceab576e 100644
--- a/gtksourceview/gtksourcecompletion.c
+++ b/gtksourceview/gtksourcecompletion.c
@@ -1,6 +1,9 @@
 /*
  * This file is part of GtkSourceView
  *
+ * Copyright 2007-2009 Jesús Barbero Rodríguez <chuchiperriman gmail com>
+ * Copyright 2009 Jesse van den Kieboom <jessevdk gnome org>
+ * Copyright 2013 Sébastien Wilmet <swilmet gnome org>
  * Copyright 2020 Christian Hergert <chergert redhat com>
  *
  * GtkSourceView is free software; you can redistribute it and/or