Update yolo11-seg custom dataset: Add supervision visuals + class remap

[LinasKo]

Description

Updated train-yolo11-instance-segmentation-on-custom-dataset.ipynb as I realized that:

1. There's no Python SDK explanation at the end, which I see as the primary use case
2. The dataset is not labelled in Latin & English, which would be the expected standard.
3. I needed to make a nice image for the blog post, and I do not want to ommit the code I used.

I also updated a few mentions of YOLOv11 to say YOLO11 (except where it concerns the dataset).

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How has this change been tested, please provide a testcase or example of how you tested the change?

I ran the entire notebook, and uploaded it here. Running it again now, just in case.
Colab: https://colab.research.google.com/drive/1rqvFpoQxXbfP63NkRfdA9JV1vIhF6RRc#scrollTo=iAgEF_7v2f3J

Any specific deployment considerations

Docs

• Docs updated? What were the changes:

[LinasKo]

@SkalskiP, because you created the notebook originally, it would be awesome if you could review this.