Add 8.x mapping to esql-for-search.md (#1189)

^

Author: leemthompo

solutions/search/esql-for-search.md

@@ -1,4 +1,6 @@
 ---
+mapped_pages:
+  - https://www.elastic.co/guide/en/elasticsearch/reference/8.18/esql-for-search.html
 applies_to:
   stack: preview
   serverless: preview