Upgrade clang-format & clang-tidy.

[hvdijk]

Overview

Upgrade clang-format & clang-tidy.

Reason for change

Describe how the current behaviour of the project is causing problems for you
or is otherwise unsatisfactory for your use case.

Description of change

We were on version 17 before, this moves us to version 19.

Anything else we should know?

If there's any other relevant information we should know that may help us in
understanding and verifying your patch, please include it here.

Checklist

• Read and follow the project Code of Conduct.
• Make sure the project builds successfully with your changes.
• Run relevant testing locally to avoid regressions.
• Run clang-format-17 on all modified code.

[coldav]

You will also need to update pull_request_template.md