### Bug description

In derivatives of `format: html` including `format: revealjs` if a `<hr>` tag is used within fences (matched pairs of `:::`) the fence breaks.

```
Using the hr tag inside of ::: causes issues

::: {.fragment}

<hr>

Example

:::
```

<img width="1075" alt="image" src="https://user-images.githubusercontent.com/9363263/191277982-aab6191a-d207-4055-a147-573a0b198670.png">

However, if we use explicit divs everything is fine:

```
But if we use explicit div tags things work

<div class="fragment">

<hr>

Example
```
<img width="1075" alt="image" src="https://user-images.githubusercontent.com/9363263/191278323-93ae9319-6f52-4253-ac7a-bd4ecf985c99.png">

Here's an entire `.qmd` example

````
---
title: "Untitled"
format: revealjs
---

Using the hr tag inside of ::: causes issues

::: {.fragment}

<hr>

Example

:::

------

But if we use explicit div tags things work

<div class="fragment">

<hr>

Example

</div>
````

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### Checklist

- [X] Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
- [X] Please [format your issue](https://quarto.org/bug-reports.html#formatting-make-githubs-markdown-work-for-us) so it is easier for us to read the bug report.
- [X] Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
- [X] Please document the operating system you're running. If on Linux, please provide the specific distribution.
2022-09-20T14:02:41Z
charliejhadley
closed
<hr> inside of fenced divs breaks the fence
https://github.com/quarto-dev/quarto-cli/issues/2519