Support GitHub "alerts" style of admonitions
To enable, add to `mkdocs.yml`:
yaml
markdown_extensions:
- github-callouts
- callouts
This can be used instead of, or in addition to, the other `callouts` extension shipped by this package.
The syntax is:
markdown
> [!NOTE]
> Lorem ipsum dolor sit amet.
This syntax is supported by GitHub and looks like this there:
> [!NOTE]
> Lorem ipsum dolor sit amet.
And on the rendered MkDocs site it looks like a typical "NOTE" admonition.
Only 5 exact types are supported, and **no** extensibility of the syntax, just like on GitHub itself.
[**More details**](https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax#alerts)