Is there a markdown to create foldable sections like in obsidian release notes?

Sure is! You can use a collapsable callout:

> [!NOTE]- This is a collapsible callout. 
> It's collapsed by default unless the reader clicks it to open it.  

To make a callout collapsible, add a dash (-) after the [!type] section like above.

You can read more about callouts here:

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