[Docs] Correct number of categories?

[chanhee-luke]

Branch

main branch https://mmdetection3d.readthedocs.io/en/latest/

📚 The doc issue

Hi! Thanks for the awesome work and the extensive annotations! :)

I have a question about the number of categories. I read in the paper that the total number of categories is over 760, but I only see 288 categories in the .pkl files for both train and validation. I assume that's why some objects have bounding boxes but are labeled as "object"? Are you planning to release annotations for more categories, or is this all?

Thanks!

-Luke

Suggest a potential alternative/fix

No response