Provide a way to create custom admonitions

[dbitouze]

It would be nice for MyST-Parser to provide a way to create custom admonitions.

My use case is the following: at the bottom of all the numerous (more than 1220) .md source files of my (LaTeX FAQ) project, I want to specify the sources of the answers to the question. I want these sources to be displayed in an admonition, say:

• which is collapsible,
• with “Source” as title,
• with the history octicon (from sphinx-design).

It would be great to be able to create my own source admonition in order to be able to type, instead of a systematic:

:::{dropdown} Source
:icon: history
⟨the source⟩
:::

just:

:::{source}
⟨the source⟩
:::

which would be as easy as:

:::{tip}
Let's give readers a helpful hint!
:::

[dbitouze]

OK, I'll manage by looking at the MyST code: thanks!

[chrisjsewell]

heya, I can see the use , but I feel this would be more of a question for sphinx in general, rather than specific to myst-parser