docs: fix bootmenu timeout description

Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

docs/formatdomain.html.in

@@ -160,9 +160,8 @@
       Since 0.8.3</span>
       Additional attribute <code>timeout</code> takes the number of milliseconds
       the boot menu should wait until it times out.  Allowed values are numbers
-      in range [0, 65535] inclusive and it is valid if and only if the previous
-      <code>enable</code> is set to "yes".
-      <span class="since"> Since 1.2.8</span>
+      in range [0, 65535] inclusive and it is ignored unless <code>enable</code>
+      is set to "yes". <span class="since">Since 1.2.8</span>
       </dd>
       <dt><code>smbios</code></dt>
       <dd>How to populate SMBIOS information visible in the guest.