### Bug description

I have encountered a problem when using Quarto in RStudio. When I attempt to parse a YAML file, I get an error message indicating a bad indentation of a mapping entry at line 9, column 8. The specific error message is YAMLError: bad indentation of a mapping entry at line 9, column 8: toc: true. I have tried various combinations of indents and spaces, but the error persists. I am unsure about what has gone wrong.

### Steps to reproduce

---
title: "Challenge 9 "
author: "Zhongyue Lin"
description: "Creating a function"
date: "6/19/2023"
format:
  html:
    df-print: paged
    toc: true
    code-copy: true
    code-tools: true
categories:
  - challenge_9
---
ERROR: YAMLError: bad indentation of a mapping entry at line 9, column 8:
        toc: true
           ^

YAMLError: bad indentation of a mapping entry at line 9, column 8:
        toc: true
           ^
    at generateError (file:///Applications/quarto/bin/quarto.js:10719:12)
    at throwError (file:///Applications/quarto/bin/quarto.js:10722:11)
    at readBlockMapping (file:///Applications/quarto/bin/quarto.js:11361:20)
    at composeNode (file:///Applications/quarto/bin/quarto.js:11528:84)
    at readBlockMapping (file:///Applications/quarto/bin/quarto.js:11346:17)
    at composeNode (file:///Applications/quarto/bin/quarto.js:11528:84)
    at readDocument (file:///Applications/quarto/bin/quarto.js:11642:5)
    at loadDocuments (file:///Applications/quarto/bin/quarto.js:11679:9)
    at load (file:///Applications/quarto/bin/quarto.js:11684:23)
    at parse3 (file:///Applications/quarto/bin/quarto.js:11694:12)

### Expected behavior

I expect the YAML file to be parsed correctly without any errors.

### Actual behavior

I expect the YAML file to be parsed correctly without any errors.

### Your environment

IDE: RStudio 2023.06.0+421
OS: macOS Monterey, Version 12.6
quarto --version 1.3.361


### 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: 1.3.361
      Path: /Applications/quarto/bin

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

[✓] Checking Python 3 installation....OK
      Version: 3.9.13 (Conda)
      Path: /Users/leo/opt/anaconda3/bin/python
      Jupyter: 4.11.1
      Kernels: python3, julia-1.8, matlab, matlab_connect, ir

[✓] 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
      knitr: 1.42
      rmarkdown: 2.20

[✓] Checking Knitr engine render......OK
2023-06-19T23:19:29Z
LeoLin990405
bug yaml-validation needs-repro stale
open
 Indentation Error with Quarto's YAML Parser
https://github.com/quarto-dev/quarto-cli/issues/5979