[8.11] Allow single fields in fields and _source parameters (#2330)

(cherry picked from commit 9f40be8)

Author: pquentin

output/schema/schema.json

@@ -23,6 +23,7 @@ import { Dictionary } from '@spec_utils/Dictionary'
 import { AggregationContainer } from '@_types/aggregations/AggregationContainer'
 import {
   ExpandWildcards,
+  Field,
   Fields,
   IndexName,
   Indices,
@@ -96,7 +97,7 @@ export class MultisearchBody {
    * Array of wildcard (*) patterns. The request returns doc values for field
    * names matching these patterns in the hits.fields property of the response.
    */
-  docvalue_fields?: FieldAndFormat[]
+  docvalue_fields?: Array<Field | FieldAndFormat>
   /**
    * Defines the approximate kNN search to run.
    * @availability stack since=8.4.0
@@ -146,7 +147,7 @@ export class MultisearchBody {
    * Array of wildcard (*) patterns. The request returns values for field names
    * matching these patterns in the hits.fields property of the response.
    */
-  fields?: Array<FieldAndFormat>
+  fields?: Array<Field | FieldAndFormat>
   /**
    * Maximum number of documents to collect for each shard. If a query reaches this
    * limit, Elasticsearch terminates the query early. Elasticsearch collects documents

output/typescript/types.ts

@@ -371,7 +371,7 @@ export interface Request extends RequestBase {
      * Array of wildcard (`*`) patterns.
      * The request returns doc values for field names matching these patterns in the `hits.fields` property of the response.
      */
-    docvalue_fields?: FieldAndFormat[]
+    docvalue_fields?: Array<Field | FieldAndFormat>
     /**
      * Defines the approximate kNN search to run.
      * @availability stack since=8.4.0
@@ -442,7 +442,7 @@ export interface Request extends RequestBase {
      * Array of wildcard (`*`) patterns.
      * The request returns values for field names matching these patterns in the `hits.fields` property of the response.
      */
-    fields?: Array<FieldAndFormat>
+    fields?: Array<FieldAndFormat | Field>
     /**
      * Defines a suggester that provides similar looking terms based on a provided text.
      */

specification/_global/msearch/types.ts

@@ -32,9 +32,9 @@ export class SourceFilter {
 
 /**
  * Defines how to fetch a source. Fetching can be disabled entirely, or the source can be filtered.
- * @codegen_names fetch, filter
+ * @codegen_names fetch, fields, filter
  */
-export type SourceConfig = boolean | SourceFilter
+export type SourceConfig = boolean | Fields | SourceFilter
 
 /**
  * Defines how to fetch a source. Fetching can be disabled entirely, or the source can be filtered.