Clarify safety and ease of use

In PR #66 a concern was raised about content saying pybioclip doesn't require ML knowledge to run. The concern is users might take this to mean they do not need to understand the limitations and biases present in the underlying model.
See https://github.com/Imageomics/pybioclip/pull/66#discussion_r1859335707 for more.

Two places may need adjustment:
- [README](https://github.com/Imageomics/pybioclip/blob/b3ac5236dd52a45d90efcfd23a2b4e670c1a9e5f/README.md?plain=1#L9)
> ... No particular understanding of ML or computer vision is required to use it. ...
- [docs/index.md](https://github.com/Imageomics/pybioclip/blob/6d7a9094368448e43f1f007687b9ddbdade1b2ac/docs/index.md?plain=1#L13
)
> No particular coding knowledge of ML or computer vision is required to use pybioclip.

Read the cited passages in README and docs/index.md, then review the concern in PR #66. Clarify the wording in both locations so ease of use is not confused with needing no understanding of the model’s limitations and biases. Done means both statements communicate that distinction consistently.

Written by the indexing model from the issue text.