docs: Update the QueryBot tutorial

[reka]

The QueryBot tutorial appears to be outdated.

• It doesn't mention the collection_name.
• Instead, it mentions an index.json.

What are the steps to update it to the new API? 🤔

1. Re-generate the tutorial with an LLM
2. Edit it.

[reka]

Consider adding a "QueryBot Usage Tips" section.

#### `QueryBot` Usage Tips

* Use a small set of files for development. E.g. if you're working on a `QueryBot` for the Pandas documentation, start with the reference documentation of a complex function like `DataFrame.query` instead of indexing the whole directory.
* Use examples where the answer can be easily verified by a human expert.