Docs: Feedback for Implementing a Custom MapStore

[davidwxy]

Hi, I have some feedback about this page

on this page the full example on YourMapStoreImplementation is loss, please fix it.
and there is another feedback also about how to write a MapStoreImplementation, in this page, there is a MongoDB client example, and add two fields named MongoClient mongoClient; MongoCollection collection; if I use other database which not support in Types of Data Connections, like SurrealDB. how to write it, it's better to give another more examples and details . thanks for read this.