Address review comments

Author: pquentin

specification/_types/Knn.ts

@@ -51,28 +51,21 @@ export interface KnnSearch {
   inner_hits?: InnerHits
 }
 
-export interface KnnQuery {
+export class KnnQuery extends QueryBase {
   /** The name of the vector field to search against */
   field: Field
   /** The query vector */
   query_vector?: QueryVector
   /** The query vector builder. You must provide a query_vector_builder or query_vector, but not both. */
   query_vector_builder?: QueryVectorBuilder
-  /** The final number of nearest neighbors to return as top hits */
-  k: long
   /** The number of nearest neighbor candidates to consider per shard */
-  num_candidates: long
+  num_candidates?: long
   /** Boost value to apply to kNN scores */
   boost?: float
   /** Filters for the kNN search query */
   filter?: QueryContainer | QueryContainer[]
   /** The minimum similarity for a vector to be considered a match */
   similarity?: float
-  /**
-   * If defined, each search hit will contain inner hits.
-   * @doc_id knn-inner-hits
-   */
-  inner_hits?: InnerHits
 }
 
 /** @variants container */