fix(cursor, doc): Add explicit return types and casts to SmartdataDbCursor methods and update getCursorExtended signature in SmartDataDbDoc.

ts/classes.doc.ts

@@ -253,7 +253,7 @@ export class SmartDataDbDoc<T extends TImplements, TImplements, TManager extends
     this: plugins.tsclass.typeFest.Class<T>,
     filterArg: plugins.tsclass.typeFest.PartialDeep<T>,
     modifierFunction = (cursorArg: plugins.mongodb.FindCursor<plugins.mongodb.WithId<plugins.mongodb.BSON.Document>>) => cursorArg,
-  ) {
+  ): Promise<SmartdataDbCursor<T>> {
     const collection: SmartdataCollection<T> = (this as any).collection;
     let cursor: plugins.mongodb.FindCursor<any> = collection.mongoDbCollection.find(
       convertFilterForMongoDb(filterArg),