[8.5] Manual prebuilt rule updates support notice (backport #4934) (#4962)

* Manual prebuilt rule updates support notice (#4934)

* Add statement to relevant pages

- Upgrade Elastic Security
- Install and manage Elastic prebuilt rules

* Update docs/detections/prebuilt-rules-management.asciidoc

Co-authored-by: Benjamin Ironside Goldstein <[email protected]>

* Update docs/upgrade/upgrade-security.asciidoc

Co-authored-by: Nastasha Solomon <[email protected]>

* Update docs/upgrade/upgrade-security.asciidoc

---------

Co-authored-by: Benjamin Ironside Goldstein <[email protected]>
Co-authored-by: Nastasha Solomon <[email protected]>
(cherry picked from commit 9ad5d70)

# Conflicts:
#	docs/detections/prebuilt-rules-management.asciidoc
#	docs/upgrade/upgrade-security.asciidoc

* Fix merge conflict

* Delete docs/detections/prebuilt-rules-management.asciidoc

Fix merge conflict

---------

Co-authored-by: Joe Peeples <[email protected]>

Author: mergify[bot]

docs/detections/rules-ui-manage.asciidoc

@@ -46,10 +46,11 @@ You can then activate whichever rules you want. If you delete any prebuilt rules
 
 [NOTE]
 ==============
-Apart from the Elastic Endpoint rule, prebuilt rules are not activated by
+* Apart from the Elastic Endpoint rule, prebuilt rules are not activated by
 default. If you want to modify a prebuilt rule, you must first duplicate it, then make your changes to the duplicated rule. All Elastic prebuilt rules are tagged with the word `Elastic`.
-
++
 To learn how to enable detection rules in Elastic Security, watch the <<enable-detection-rules, tutorial>> at the end of this topic.
+* Automatic updates of Elastic prebuilt rules are supported for the current {elastic-sec} version and the latest three previous minor releases. For example, if you’re on {elastic-sec} 8.10, you’ll be able to use the Rules UI to update your prebuilt rules until {elastic-sec} 8.14 is released. After that point, you can still manually download and install updated prebuilt rules, but you must upgrade to the latest {elastic-sec} version to receive automatic updates.
 ==============
 
 [float]

docs/upgrade/upgrade-security.asciidoc

@@ -40,6 +40,14 @@ For large deployments with more than 10 {kib} instances, and more than 10,000 sa
 you can reduce the upgrade downtime by bringing up a single {kib} instance and waiting for it to
 complete the upgrade migration before bringing up the remaining instances.
 
+IMPORTANT: You can upgrade to pre-release versions for testing,
+but upgrading from a pre-release to the Generally Available version is unsupported.
+You should use pre-release versions only for testing in a temporary environment.
+
+[float]
+=== Support for Elastic prebuilt detection rule automatic updates
+<<load-prebuilt-rules,Automatic updates of Elastic prebuilt detection rules>> are supported for the current {elastic-sec} version and the latest three previous minor releases. For example, if you’re upgrading to {elastic-sec} 8.10, you’ll be able to use the Rules UI to update your prebuilt rules until {elastic-sec} 8.14 is released. After that point, you can still manually download and install updated prebuilt rules, but you must upgrade to the latest {elastic-sec} version to receive automatic updates.
+
 [float]
 [[preventing-migration-failures]]
 === Preparing for migration