Visual editor un-nests spans

[andrewpbray]

Bug description

When authoring slides in revealjs format, the following slide, featuring nested spans, renders as intended: each fragment fading in on click, each with a colored span, all in the same paragraph.

---
format: revealjs
---

## Title

::: {style="text-align: center"}
[One [hen]{style="color: red"}]{.fragment} [two [ducks]{style="color: blue"}]{.fragment}
:::

When I click into the visual editor, then click back, the sourced has been changed to:

---
format: revealjs
---

## Title

::: {style="text-align: center"}
[One ]{.fragment}[hen]{style="color: red"} [two ]{.fragment}[ducks]{style="color: blue"}
:::

In other words, it unnests the spans, which has the effect of breaking the animation.

I can fix the animation by putting the fade in fragments as divs instead of spans, but then it breaks the all-in-one-paragraph layout.

This is using the RStudio IDE 2022.07.0 Build 548 "Spotted Wakerobin" on MacOS Catalina 10.15.7.

Thanks for the help!

quarto check Output

[✓] Checking Quarto installation......OK
      Version: 1.0.20
      Path: /Applications/quarto/bin

[✓] Checking basic markdown render....OK

[✓] Checking Python 3 installation....OK
      Version: 3.9.1
      Path: /usr/local/bin/python3
      Jupyter: 4.11.0
      Kernels: python3

[✓] Checking Jupyter engine render....OK

[✓] Checking R installation...........OK
      Version: 4.2.1
      Path: /Library/Frameworks/R.framework/Resources
      LibPaths:
        - /Library/Frameworks/R.framework/Versions/4.2/Resources/library
      rmarkdown: 2.14

[✓] Checking Knitr engine render......OK

quarto tools check Output

[✓] Inspecting tools

Tool         Status            Installed     Latest  
chromium     Not installed     ---           869685  
tinytex      Not installed     ---           v2022.07

[vezwork]

I was able to reproduce this issue with the visual editor in the vscode extension. It looks correct in the visual editor but breaks upon saving and switching back to the source editor.