Code fences in Slides don't get syntax highlighting.

[ayhon]

I was testing Obsidian's core plugin "Slides" when I noticed that syntax highlighting didn't seem to work for Lean files. The issue doesn't seem to happen for other languages like python.

I tested another plugin which adds syntax highlighting and they don't seem to have this same issue, which is what prompted me to open an issue here.

I may look into submitting a PR

[tomaz1502]

Thanks! Feel free to submit a PR. Otherwise I can look into it.