[Docs] - Add Warning about Version Downgrade and Alerting to Grafana … (#64896)

* [Docs] - Add Warning about Version Downgrade and Alerting to Grafana v9.4 Upgrade Instructions

Add Warning about Version Downgrade and Alerting to Grafana v9.4 Upgrade Instructions

* Update docs/sources/upgrade-guide/upgrade-v9.4/index.md

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>

* Update docs/sources/upgrade-guide/upgrade-v9.4/index.md

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>

* makes prettier

---------

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>
Co-authored-by: Chris Moyer <chris.moyer@grafana.com>

docs/sources/upgrade-guide/upgrade-v9.4/index.md

@@ -16,4 +16,4 @@ weight: 1995
 
 ## Technical notes
 
-There are no additional upgrade steps to complete for this version of Grafana.
+The upgrade to Grafana v9.4 includes changes to the Grafana database for Grafana alerting that are not backward compatible. As a result, when you upgrade to Grafana v9.4, do not downgrade your Grafana instance to an earlier version. Doing so might cause issues with managing your Grafana alerts.