`end` is used as a key word in `case when` clause

* docs: update csharp connector status

* docs: fix csharp ws bulk pulling

* docs: clarify database param is optional to websocket dsn

* test(docs):update docs-example file structure

* test(docs):update docs-example references under zh and en

Remove case sensitive description of quotes and other minor content.

将SELECT SERVER_VERSION()改为SELECT SERVER_STATUS()

* docs(diver):C# add docs with WebSocket

* docs(driver):C# docs update with commnets

This is the Juptyerlab doc for 3.0