Add required reason for hold

Change-Id: Ia3b5b513731c784780bc8aa61f388b2a42d7d794
diff --git a/doc/source/admin/client.rst b/doc/source/admin/client.rst
index 5cdf919..961b205 100644
--- a/doc/source/admin/client.rst
+++ b/doc/source/admin/client.rst
@@ -28,7 +28,7 @@
 
 Example::
 
-  zuul autohold --tenant openstack --project example_project --job example_job ---count 1
+  zuul autohold --tenant openstack --project example_project --job example_job --reason "reason text" --count 1
 
 Enqueue
 ^^^^^^^