docs: update theme 1.9.2

[dgarcia360]

Updates docs theme to 1.9.2.

CHANGELOG: https://github.com/scylladb/sphinx-scylladb-theme/blob/master/docs/source/upgrade/CHANGELOG.md#192---14-april-2026

[annastuchlik]

@dkropachev Please merge.

[roydahan]

This repository is EOL, please do not open new PRs for it.

[annastuchlik]

@roydahan The repository may be EOL, but we still publish the docs at https://cpp-driver.docs.scylladb.com/.
As long as we publish the docs, we need to update the Sphinx theme.
One reason is that we need to update dependencies to prevent security vulnerabilities.

Please, keep merging the Sphinx theme updates like this one as long as you want to keep the documentation alive.

[roydahan]

So maybe we should stop publish its docs.

[annastuchlik]

So maybe we should stop publish its docs.

@roydahan Thank you for merging this PR.
I'd be happy to take down the docs for this driver and stop opening PRs in this repo, but it's not my call. It was decided to mark the driver as deprecated, but keep publishing the docs. Perhaps it's worth reconsidering?