[typespec-ts] some feedback from CC reviewer

Here are some feedback from copilot code reviewer on the DPG generated code. Do we want to address any of these?

1. missing ref docs for package

2. missing ref doc for client:

3. RestError from streaming response (I am not sure whether this is valid though)

https://github.com/Azure/azure-sdk-for-js/pull/39230/changes/c2c71800fa5696a5bc632a0ca57199401940f919

Start by reviewing the typespec-ts DPG generated code and the three reviewer findings in the issue, then inspect the referenced Azure SDK pull request for the streaming RestError example. Confirm which findings are valid with the project context; done means the agreed documentation or behavior changes are addressed, or the invalid findings are clearly resolved with an explanation.

Written by the indexing model from the issue text.