fix lint and address code review comments

Author: vkarpov15

lib/model.js

@@ -3688,7 +3688,7 @@ Model.castObject = function castObject(obj, options) {
     }
 
     if (schemaType.$isMongooseDocumentArray) {
-      const castNonArraysOption = schemaType.options?.castNonArrays ??schemaType.constructor.options.castNonArrays;
+      const castNonArraysOption = schemaType.options?.castNonArrays ?? schemaType.constructor.options.castNonArrays;
       if (!Array.isArray(val)) {
         if (!castNonArraysOption) {
           if (!options.ignoreCastErrors) {

types/indexes.d.ts

@@ -10,7 +10,7 @@ declare module 'mongoose' {
   function syncIndexes(options?: SyncIndexesOptions): Promise<ConnectionSyncIndexesResult>;
 
   interface IndexManager {
-    /* Deletes all indexes that aren't defined in this model's schema. Used by `syncIndexes()`. */
+    /* Deletes all indexes that aren't defined in this model's schema. Used by `syncIndexes()`. Returns list of dropped index names. */
     cleanIndexes(options?: { toDrop?: string[], hideIndexes?: boolean }): Promise<string[]>;
 
     /**