Bump pygments from 2.14.0 to 2.15.0 in /docs/sphinx (#812)

Bumps [pygments](https://github.com/pygments/pygments) from 2.14.0 to 2.15.0.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](https://github.com/pygments/pygments/compare/2.14.0...2.15.0)

---
updated-dependencies:
- dependency-name: pygments
  dependency-type: indirect
...

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[ROCm/rccl commit: c671f70ef3]

projects/rccl/docs/sphinx/requirements.txt

@@ -74,7 +74,7 @@ pydata-sphinx-theme==0.13.3
     #   sphinx-book-theme
 pygithub==1.58.1
     # via rocm-docs-core
-pygments==2.14.0
+pygments==2.15.0
     # via
     #   accessible-pygments
     #   pydata-sphinx-theme