[DOCS] Removed differencies between text and code (#27993)

docs/reference/aggregations/metrics/cardinality-aggregation.asciidoc

@@ -5,8 +5,7 @@ A `single-value` metrics aggregation that calculates an approximate count of
 distinct values. Values can be extracted either from specific fields in the
 document or generated by a script.
 
-Assume you are indexing books and would like to count the unique authors that
-match a query:
+Assume you are indexing store sales and would like to count the unique number of sold products that match a query:
 
 [source,js]
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