chore(deps): update dependency pypandoc to v1.16 (#881)

This PR contains the following updates:

| Package | Change | Age | Confidence |
|---|---|---|---|
| [pypandoc](https://redirect.github.com/JessicaTegner/pypandoc) |
`==1.15` -> `==1.16` |
[![age](https://developer.mend.io/api/mc/badges/age/pypi/pypandoc/1.16?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/pypandoc/1.15/1.16?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

---

### Release Notes

<details>
<summary>JessicaTegner/pypandoc (pypandoc)</summary>

###
[`v1.16`](https://redirect.github.com/JessicaTegner/pypandoc/compare/v1.15...v1.16)

[Compare
Source](https://redirect.github.com/JessicaTegner/pypandoc/compare/v1.15...v1.16)

</details>

---

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requirements-dev.txt

@@ -5,6 +5,6 @@ tox==4.30.3 ; python_version < "3.10"
 wheel==0.46.1
 Sphinx==7.4.7
 sphinx-rtd-theme==3.0.2
-pypandoc==1.15
+pypandoc==1.16
 twine==6.2.0
 black==25.9.0