[gnome-chess] help: Cover clock type

[Andre Klapper <aklapper src gnome org>]

commit 4240bc85ffcdba930b5bb1d181f37f31435aefdd
Author: Andre Klapper <a9016009 gmx de>
Date:   Wed Sep 5 16:20:47 2018 +0200

    help: Cover clock type

 help/C/timer.page | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/help/C/timer.page b/help/C/timer.page
index ee52db7..78d5b2f 100644
--- a/help/C/timer.page
+++ b/help/C/timer.page
@@ -27,6 +27,8 @@
       <p>Under <gui>Time limit</gui>, change
       <gui style="menuitem">No limit</gui> to the time that each player
       has in total for the game.</p>
+      <p>You can also change the <gui>Clock type</gui> if you do not want a
+      simple clock that counts down.</p>
     </item>
   </steps>