Refs #35347 - Add trends & statistics warning

guides/doc-Release_Notes/topics/foreman.adoc

@@ -58,3 +58,6 @@ It is safe to remove the file or remove all content.
 * External node classifier https://projects.theforeman.org/issues/35326[renames hostname and fqdn parameters].
   In Foreman 2.4 https://projects.theforeman.org/issues/31168[the hostname and fqdn parameters were added], but this overrides with the facts in Puppet.
   The parameters are now prefixed by `foreman_`.
+* Trends and statistics https://projects.theforeman.org/issues/35347[will be removed] unless https://github.com/theforeman/foreman_statistics[foreman_statistics] is installed.
+  This data used to be part of Foreman, but was extracted to a plugin in Foreman 2.3.
+  Until now this data was kept in the database, but now this data will be purged unless the plugin is installed.