### Bug description

When using automatically extracted listing descriptions, descriptions are kept empty when the rendered content does not contain a paragraph. Content can have quite a bit of text (within lists, for example), and depending on the presentation of those lists, the description can be empty.

### Steps to reproduce

Given a Quarto website project using the `_quarto.yml`:

````yaml
project:
  type: website

website:
  title: Some Product Documentation
  site-url: https://docs.example.com/product/news/
  navbar:
    left:
      - text: "home"
        file: index.qmd
````

The `index.qmd` page:

````markdown
---
title: Some Product Release Notes
listing:
    contents: releases
    type: default
    feed: true
    sort: "version desc"
format:
    html:
        toc-depth: 2
---

## Introduction

The notes for each release follow.
````

The three `releases/2023.05.0.md`, `releases/2023.03.0.md`, and `releases/2023.01.0d` files:

````markdown
---
title: Some Product 2023.05.0
version: 2023.05.0
date: May 10, 2023
---

## New

*   This is a thing that is new.

*   This is another thing that is new.

## Fixed

*   This is a fixed thing.
````

````markdown
---
title: Some Product 2022.03.0
version: 2023.03.0
date: March 24, 2022
---

## New

*   This is a thing that is new.
````

````markdown
---
title: Some Product 2023.01.0
version: 2023.01.0
date: Jan 15, 2023
---

## New

*   This is a compact list that declares new things.
*   There are lots of words here, but the list is kept compact.

## Fixed

*   This is a fixed thing.
````

Render or preview this site.

### Expected behavior

The listing view should should include text from each item and retain the list-like nature of the content.

### Actual behavior

When rendered, not all items have content and those that do have lost their list presentation.

<img width="528" alt="image" src="https://github.com/quarto-dev/quarto-cli/assets/362187/4488077c-f20a-417f-b071-1dc6e5d9ba8d">

In this example, the 2023.05.0 item has list items separated by blank lines, meaning it is styled as lists with paragraph items. This is enough for the listing code to extract the item text the item description.

The 2023.03.0 item has a one-element list. Because there is only one list item, it is not given paragraphs for its items.

The 2023.01.1 item has multiple lists, but they do not have blank lines separating the items, which causes them to be styled as lists without paragraphs. The lack of paragraphs means that the listing item description is empty.

### Your environment

- OS: macOS Monterey 12.6.5

### Quarto check output

```
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.1.1: OK
      Dart Sass version 1.55.0: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.3.340
      Path: /Applications/RStudio.app/Contents/Resources/app/quarto/bin

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

[✓] Checking Python 3 installation....OK
      Version: 3.9.6
      Path: /Library/Developer/CommandLineTools/usr/bin/python3
      Jupyter: (None)

      Jupyter is not available in this Python installation.
      Install with python3 -m pip install jupyter

[✓] Checking R installation...........OK
      Version: 3.6.3
      Path: /Library/Frameworks/R.framework/Resources
      LibPaths:
        - /Library/Frameworks/R.framework/Versions/3.6/Resources/library
      knitr: 1.42.8
      rmarkdown: 2.20

[✓] Checking Knitr engine render......OK
```
dragonstyle
2023-05-30T12:45:20Z
aronatkins
bug
v1.4
open
extraction of listing item description needs paragraphs
https://github.com/quarto-dev/quarto-cli/issues/5742