corrected a parameter description

Author: HeidiSteen

articles/search/semantic-how-to-query-request.md

@@ -288,7 +288,9 @@ The following example in this section uses the [hotels-sample-index](search-get-
 
    Answers (and captions) are extracted from passages found in fields listed in the semantic configuration. This is why you want to include content-rich fields in the prioritizedContentFields of a semantic configuration, so that you can get the best answers and captions in a response. Answers aren't guaranteed on every request. To get an answer, the query must look like a question and the content must include text that looks like an answer.
 
-1. Set "captions" to specify whether semantic captions are included in the result. Currently, the only valid value for this parameter is "extractive". Captions can be configured to return results with or without highlights. The default is for highlights to be returned. This example returns captions without highlights: `extractive|highlight-false`. 
+1. Set "captions" to specify whether semantic captions are included in the result. If you're using a semantic configuration, you should set this parameter. While the ["searchFields" approach](#2b---use-searchfields-for-field-prioritization) automatically included captions, "semanticConfiguration" does not. 
+
+   Currently, the only valid value for this parameter is "extractive". Captions can be configured to return results with or without highlights. The default is for highlights to be returned. This example returns captions without highlights: `extractive|highlight-false`. 
 
 1. Set "highlightPreTag" and "highlightPostTag" if you want to override the default highlight formatting that's applied to captions.