Docs: connecting to azure data explorer

I have a few questions regarding to the code about connecting to data explorer.

- Is it correct that this piece of code provide a connection to data explorer?
- What do the three parameters mean?
- How and where can the parameter values be found for the user?
- Does TSItoken stand for time series insight token and if so, why is this referred to time series insight?

` const cluster = new ADX.ADXTrenderClient(
"https://help.kusto.windows.net/",
authContext.getTsiToken,
"Trender"
);
`

`

Start by locating the TypeScript entry point that constructs ADX.ADXTrenderClient and tracing authContext.getTsiToken. Document what the three arguments represent, where users obtain their values, and whether TSItoken refers to Time Series Insights; done means these connection details and terminology are answered in the documentation.

Written by the indexing model from the issue text.