Added a note on incremental enrichment capabilities

Author: Luis Cabrera

articles/search/search-sku-tier.md

@@ -86,6 +86,8 @@ For [AI enrichment](cognitive-search-concept-intro.md), you should plan to [atta
 | [Built-in cognitive skills](cognitive-search-predefined-skills.md) | Billed at the same rate as if you had performed the task by using Cognitive Services directly. |
 | Custom skills | A custom skill is functionality you provide. The cost of using a custom skill depends entirely on whether custom code is calling other metered services. |
 
+The [incremental enrichment (preview)](cognitive-search-incremental-indexing-conceptual.md) feature allows you to provide a cache that enables the indexer to be more efficient at running only the cognitive skills that are necessary if you modify your skillset in the future, saving you time and money.
+
 <a name="search-units"></a>
 
 ## Billing formula (R x P = SU)