[DOCS] Specifies no known issues (elastic#1537)

Author: KOTungseth

docs/release-notes/known-issues.md

@@ -5,6 +5,8 @@ navigation_title: "Known issues"
 
 # Elastic APM Ruby Agent known issues [elastic-apm-ruby-agent-known-issues]
 
+Known issues are significant defects or limitations that may impact your implementation. These issues are actively being worked on and will be addressed in a future release. Review the Elastic APM Ruby Agent known issues to help you make informed decisions, such as upgrading to a new version.
+
 % Use the following template to add entries to this page.
 
 % :::{dropdown} Title of known issue
@@ -17,4 +19,6 @@ navigation_title: "Known issues"
 % **Resolved**
 % On [Month/Day/Year], this issue was resolved.
 
-:::
+:::
+
+_No known issues_