Add codespell support (config, workflow to detect/not fix) and make it fix few typos

[yarikoptic]

Was lead here by a YouTube video... decided to check things out ;-)

More about codespell: https://github.com/codespell-project/codespell .

I personally introduced it to dozens if not hundreds of projects already and so far only positive feedback.

CI workflow has 'permissions' set only to 'read' so also should be safe.

[0atman]

interesting, how does it compare to languagetool?

[yarikoptic]

dunno since I never used languagetool! But from its description of being a "spellchecker" I would assume that the principled difference is that codespell just corrects typos it has in its dictionaries, not all possible spell fixes. This way it achieves quite low false positives rate.