Docs still mention old way Function ID is generated

[Charles-Gagnon]

The docs here still mentioned the function ID being made from the HostID + class/method name, which isn't accurate anymore after #1071

https://github.com/Azure/azure-functions-sql-extension/blob/main/docs/TriggerBinding.md#az_funcleasestablename

There may be other places in the docs this is mentioned as well, we should ensure that everything is updated with the latest state to avoid confusion.

[Charles-Gagnon]

@MaddyDev Assigning this to you as follow up to your PR

[MaddyDev]

Fixed #1109