Micro updates

[maclandrol]

Changelogs

• Improve documentation and docstrings
• Reviewed tutorial and correct typos
• Fix some small bugs
• Change doc color to have some distinct identity compared to graphium [to-be-discussed]

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Checklist:

• Was this PR discussed in an issue? It is recommended to first discuss a new feature into a GitHub issue before opening a PR.
• Add tests to cover the fixed bug(s) or the new introduced feature(s) (if appropriate).
• Update the API documentation is a new function is added, or an existing one is deleted.
• Write concise and explanatory changelogs above.
• If possible, assign one of the following labels to the PR: feature, fix or test (or ask a maintainer to do it for you).

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Did a global pass. Tutorial for the functional API are mostly the only thing missing.

[hadim]

Thanks Manu. That looks great! (and will help even more an LLM to read the doc :-D)

I have logged an issue for the functional tuto/guide. I'll take care of it before the release.