Provide a way to hide (or at least not look strange) in standard markdown

[rootwork]

Here's my use case: I have documentation that lives both on a Docusaurus site and in a navigable GitHub repo. The admonitions look great on the Doc site of course, but in GitHub, I just get the standard rendered Markdown, which is:

:::info Foo

Bar

:::

Which isn't that pretty, and if the title is long-ish can actually be hard to visually parse.

• The easiest solution that I could think of would be to support admonitions inside HTML comments, so that both :::info (etc.) and <!--:::info--> (etc), ::: and <!--:::--> would be valid and result in rendered admonitions. Then in standard Markdown contexts, those lines just wouldn't appear. You'd lose the admonition-type and any custom titles, but that'd be better than nothing.

• Or, if admonitions were supported (or parsed from) titles, something like this:

## <!--:::info--> Foo

Bar

<!--:::-->

could render like this in standard Markdown contexts:

Foo

Bar

• But perhaps there would be other ways to accomplish the same thing. Any thoughts?