chore: add typos spell checker

[joscha]

This adds the typos spell checker on CI and locally.

Locally it can be executed via:

• typos to check
• typos --write-changes to check and write changes to disk

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.