Website sitemap.xml does not include pdf files

Bug description

Problem:
When building a website, the autogenerated sitemap.xml does not include pdf files, for example academic publications in a subdirectory.

In my case, I have a subfolder /publications/ with many pdf files which I link to through a listing page. But the pdfs do not show up in the sitemap. I could also not find documentation about how to configure the sitemap.

Steps to reproduce

No response

Expected behavior

1. automatically list all pdfs that are copied into the _site/ folder in the sitemap or
2. automatically list all pdfs that are linked via another page and copied into the _site/ folder or
3. provide an option to list pdfs (or other files) to be included in the sitemap

Actual behavior

No response

Your environment

No response

Quarto check output

Quarto 1.6.40
[✓] Checking environment information...
Quarto cache location: /home/alarith/.cache/quarto
[✓] Checking versions of quarto binary dependencies...
Pandoc version 3.4.0: OK
Dart Sass version 1.70.0: OK
Deno version 1.46.3: OK
Typst version 0.11.0: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
Version: 1.6.40
Path: /opt/quarto/bin

[✓] Checking tools....................OK
TinyTeX: (not installed)
Chromium: (not installed)

[✓] Checking LaTeX....................OK
Using: Installation From Path
Path: /usr/bin
Version: 2023

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

[✓] Checking Python 3 installation....OK
Version: 3.12.3
Path: /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: 4.4.2
Path: /usr/lib/R
LibPaths:
- /home/alarith/R/x86_64-pc-linux-gnu-library/4.4
- /usr/local/lib/R/site-library
- /usr/lib/R/site-library
- /usr/lib/R/library
knitr: 1.49
rmarkdown: 2.29

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

Start by reproducing the issue with Quarto 1.6.40 using a /publications/ subfolder containing PDF files and inspect the generated sitemap.xml. No source file or test is identified in the report; done means establishing whether copied or linked PDFs should be included and implementing or documenting a supported way to produce that result.