Fix duration in Notification.rakudoc from minutes to seconds

Corrected the duration from 60 minutes to 60 seconds in the documentation, as `sleep` is expressed in seconds.

Author: lizmat

doc/Type/IO/Notification.rakudoc

@@ -44,7 +44,7 @@ sleep 60;
 
 This snippet of code sets a watch on the system log file, emitting the kind
 of event that has occurred or capturing an error otherwise; the created
-L<C<Supply>|/type/Supply> is tapped, and the event printed. It does so for 60 minutes,
+L<C<Supply>|/type/Supply> is tapped, and the event printed. It does so for 60 seconds,
 emitting something like this:
 
 =for code :lang<text>