[Markdown Render] Lack of code block corner radius

[swiftyfinch]

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Bug

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Hello! I've noticed that a code block corner radius equals zero in some cases.
Checked in Safari (17.0) and Chrome (122.0.6261.94).

This looks like a bug:

https://github.com/swiftyfinch/Rugby/blob/2.5.2/Docs/how-to-install.md

This is fine:

https://github.com/swiftyfinch/Rugby/releases/tag/2.5.2

And this is fine too:

# Corner radius