[DOCS] Removees 8.0 from Upgrade Assistant docs (elastic#69067)

# Conflicts:
#	docs/management/upgrade-assistant/index.asciidoc

docs/management/upgrade-assistant/index.asciidoc

@@ -2,14 +2,16 @@
 [[upgrade-assistant]]
 == Upgrade Assistant
 
-The Upgrade Assistant helps you prepare for your upgrade to {es} 9.0.
-To access the assistant, open the menu, then go to *Stack Management > {es} > 9.0 Upgrade Assistant*.
+The Upgrade Assistant helps you prepare for your upgrade to the next major {es} version.
+For example, if you are using 6.8, the Upgrade Assistant helps you to upgrade to 7.0.
+To access the assistant, open the menu, then go to *Stack Management > {es} > Upgrade Assistant*.
 
 The assistant identifies the deprecated settings in your cluster and indices
 and guides you through the process of resolving issues, including reindexing.
 
-Before upgrading to Elasticsearch 8.0, make sure that you are using the final
-7.x minor release to see the most up-to-date deprecation issues.
+Before you upgrade, make sure that you are using the latest released minor
+version of {es} to see the most up-to-date deprecation issues.
+For example, if you want to upgrade to to 7.0, make sure that you are using 6.8.
 
 [float]
 === Reindexing