[8.8] Document the new Maintenance Windows feature (backport #3253) (#…

…3321)

Co-authored-by: Joe Peeples <joe.peeples@elastic.co>
Co-authored-by: Nastasha Solomon <79124755+nastasha-solomon@users.noreply.github.com>

docs/detections/rules-ui-manage.asciidoc

@@ -139,6 +139,8 @@ Similarly, rules will be skipped if they can't be modified by a bulk edit. For e
 ** *Add rule actions*: Add <<rule-notifications,notification actions>> on all selected rules.
 +
 NOTE: The action frequency you select applies to all actions (both new and existing) on all selected rules. If you don't want to change the frequency of existing actions, update the rules separately.
++
+NOTE: Rule actions won't run during a {kibana-ref}/maintenance-windows.html[maintenance window]. They'll resume running after the maintenance window ends.
 
 ** *Update rule schedules*: Update the <<rule-schedule,schedules>> and look-back times on all selected rules.
 ** *Apply Timeline template*: Apply a specified <<timeline-templates-ui, Timeline template>> to the selected rules. You can also choose *None* to remove Timeline templates from the selected rules.