feat: add mode to settings types (#1439)

Author: cdhawke

packages/client-search/src/types/Settings.ts

@@ -305,6 +305,11 @@ export type Settings = {
    */
   readonly relevancyStrictness?: number;
 
+  /**
+   * The search mode that the index will use to query for results.
+   */
+  readonly mode?: 'neuralSearch' | 'keywordSearch';
+
   /**
    * Content defining how the search interface should be rendered.
    * This is set via the settings for a default value and can be overridden via rules