ci: Check spelling with codespell

[spetrosi]

• You can ignore words inline by adding a comment like # codespell:ignore word.
• You can ignore words by adding them to the .codespell_ignores file.
• You can ignore files and directories by adding them with skip = to the .codespellrc file.

[spetrosi]

@richm how does it look like? Here is the new workflow in action: linux-system-roles/timesync#267

I implemented a workaround for finding not-inclusive words as substring - reporting "master" in "timemaster" by using codespell's --regex argument, it allows to tell codespell what regex use to find words that it then compares literally to wrods in a dictionary. With this argument I provide a regex listing all the prohibited words with OR. See https://github.com/linux-system-roles/.github/pull/83/files#diff-72f9ba5d2a38c1ef7cbff07f2730afebeb30869bcb0c860b28c1b57e30a4feb2R20 and https://github.com/linux-system-roles/timesync/actions/runs/13180437334/job/36789627576?pr=267#step:6:21
Not a very clean workaround tbh, but codespell doesn't support adding words to dictionary as regex. The workaround is to

Codespell community is active, I have a PR for the action in review codespell-project/actions-codespell#86. So far, I am running the action from my fork.

Codespell has some nice features like the ability to ignore per-line, ignore files and dirs, disable and enable checking within files. Comparing it to woke, codespell doesn't provide different levels of report like warning and error, any match is reported as an error.
It has a built-in dictionary in https://github.com/codespell-project/codespell/blob/main/codespell_lib/data/dictionary_usage.txt, however we can use write our own dictionary too.

I honestly don't remember what else we didn't like about woke.

[richm]

One minor nit, otherwise, lgtm