[RAM][Maintenance Window] MW scoped query language improvements (#172993

)

## Summary

Some language improvements for maintenance window scoped queries.

### Before


![image](https://github.com/elastic/kibana/assets/74562234/f9fa39f9-f057-4dc5-9a6f-91ef85f0de79)


### After


![image](https://github.com/elastic/kibana/assets/26471269/c6e409cd-634a-4c62-b85d-6ad867afe4cd)

---------

Co-authored-by: Kibana Machine <[email protected]>
Co-authored-by: Lisa Cawley <[email protected]>

x-pack/plugins/alerting/public/pages/maintenance_windows/translations.ts

@@ -211,15 +211,15 @@ export const CREATE_FORM_CATEGORY_STACK_RULES = i18n.translate(
 export const CREATE_FORM_SCOPED_QUERY_TITLE = i18n.translate(
   'xpack.alerting.maintenanceWindows.createForm.scopedQuery.title',
   {
-    defaultMessage: 'Define scope of rules',
+    defaultMessage: 'Filters',
   }
 );
 
 export const CREATE_FORM_SCOPED_QUERY_DESCRIPTION = i18n.translate(
   'xpack.alerting.maintenanceWindows.createForm.scopedQuery.description',
   {
     defaultMessage:
-      'Use KQL to further narrow down the alerts affected by this maintenance window.',
+      'Add filters that refine the scope of the maintenance window. You can select only one category when filters are enabled.',
   }
 );