Mention usage of related finetunes

[rasbt]

I added an additional info box under the model list in hope that it makes this info more prominent. I think it might not hurt as it is sometimes overlooked by users.

[Andrei-Aksionov]

I think it's a better placement.
But what about this: https://github.com/Lightning-AI/litgpt/blob/main/tutorials/download_model_weights.md#finetunes-and-other-model-variants
You want to keep it?

[rasbt]

I think it doesn't hurt to keep it because it can be linked directly via the hyperlink ref whereas the box can't unfortunately.

[carmocca]

I find it odd to have the block of text twice in the same file