[Docs] add known issue (#190762)

## Summary

Add known issue in `8.15.0` to the _docs/changelog_ file and link its
corrisponding PR fix for `8.15.1`+

docs/CHANGELOG.asciidoc

@@ -74,9 +74,27 @@ Review important information about the {kib} 8.x releases.
 [[release-notes-8.15.0]]
 == {kib} 8.15.0
 
-
 For information about the {kib} 8.15.0 release, review the following information.
 
+The 8.15.0 release includes the following known issues.
+
+[float]
+[[known-issues-8.15.0]]
+=== Known issues
+
+[discrete]
+[[known-178114]]
+.Kibana fails to start when processing YAML configuration keys that contain dotted notation in objects in arrays
+[%collapsible]
+====
+*Details* +
+In 8.15.1, We fixed a bug when processing YAML configuration keys that contain dotted notation in objects in arrays.
+This can manifest as a validation error causing Kibana to not start.
+
+For more information, refer to {kibana-pull}190590[#190590].
+====
+
+
 [float]
 [[deprecations-8.15.0]]
 === Deprecations