weston.man: Document the way to disable idle timeout
diff --git a/man/weston.man b/man/weston.man
index e7692c7..39d854b 100644
--- a/man/weston.man
+++ b/man/weston.man
@@ -117,6 +117,7 @@
user input for the idle timeout, Weston enters an inactive mode. The
screen fades to black, and depending on the shell in use, a screensaver
may activate, monitors may switch off, and the shell may lock the session.
+A value of 0 effectively disables the timeout.
.TP
\fB\-\-log\fR=\fIfile.log\fR
Append log messages to the file