improve changelog

Author: smalyshev

docs/changelog/128163.yaml

@@ -1,12 +1,15 @@
 pr: 128163
 summary: Make `skip_unavailable` catch all errors
-area: CCS
-type: "breaking, enhancement"
-issues: []
+area: ES|QL
+type: breaking
+issues: [ ]
 breaking:
-  title: Make `skip_unavailable` catch all errors
-  area: CCS
-  details: Please describe the details of this change for the release notes. You can
-    use asciidoc.
-  impact: Please describe the impact of this change to users
+  title: `skip_unavailable` catches all runtime errors
+  area: ES|QL
+  details: If `skip_unavailable` is set to `true`, the runtime errors from this cluster do not lead
+    to a failure of the query. Instead, the cluster is set to `skipped` or `partial status, and the query
+    execution continues. This is a breaking change from previous versions, where `skip_unavailable` only applied
+    to errors related to cluster being unavailable.
+  impact: The errors on remote clusters, e.g. missing indices, will not lead to a failure of the query.
+    Instead, the cluster is set to `skipped` or `partial status in the response metadata.
   notable: false