[codespell] Fix spelling mistakes codespell 2.2.6

What this MR does / why does DuMux need it:

Codespell has been updated to 2.2.6 and newly detected spelling mistakes have been corrected to fix the pipeline.

Notes for the reviewer

Did we want to fully fix the version of codespell? Currently with ~=2.2.2 minor updates with new errors still happen automatically.

Before you request a review from someone, make sure to revise the following points:

• does the new code follow the style guide?
• do the test pipelines pass? (see guide on how to run pipelines for a merge request)
• is the code you changed and/or the new code you wrote covered in the test suite? (if not, extend the existing tests or write new ones)
• does your change affect public interfaces or behavior, or, does it introduce a new feature? If so, document the change in CHANGELOG.md.
• is the list of the header includes complete? ("include what you use")
• all files have to end with a \n character. Make sure there is no \ No newline at end of file comment in "Changes" of this MR.
• (if not applicable remove) if the examples are modified, is the documentation regenerated (using generate_example_docs.py)