[gnome-klotski] Fix licensing information in help.

[Arnaud B. <arnaudb src gnome org>]

commit 0e988cc00a5d2c1cfb373067ff3e9498795d7095
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Fri Feb 14 06:27:09 2020 +0100

    Fix licensing information in help.

 help/C/index.docbook | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/help/C/index.docbook b/help/C/index.docbook
index a0ae905..7ae6652 100644
--- a/help/C/index.docbook
+++ b/help/C/index.docbook
@@ -172,9 +172,8 @@
 
        <para> This program is distributed under the terms of the GNU
        General Public license as published by the Free Software
-       Foundation; either version 2 of the License, or (at your option)
-       any later version. A copy of this license can be found at this
-       <ulink url="help:gpl" type="help">link</ulink>, or in the file
+       Foundation; either version 3 of the License, or (at your option)
+       any later version. A copy of this license can be found in the file
        COPYING included with the source code of this program. </para>
 
        <para>