[Feature Request]: Make pretty notes/tips/warnings more compatible to GitHub

[hirasso]

Describe the problem 🧐

Not sure how we missed this when we implemented our custom info boxes: There is a convention to display nicer looking boxes on GitHub! It works like this: https://github.com/orgs/community/discussions/16925

Our info boxes don't follow this convention, yet.

Describe the propsed solution 😎

I'd like to migrate all our boxes so that they look great both on swup.js.org as well as on GitHub.

Alternatives considered 🤔

Ignore it

How important is this feature to you? 🧭

Nice to have

Checked all these? 📚

• [X] I have read and searched the official docs
• [X] I have checked discussions and existing issues for related problems
• [X] I agree to follow this project's Code of Conduct
• [X] I have provided all necessary information to the best of my knowledge

[daun]

This was actually implemented in #187.