Add write_registers support for Fan Mode

[crug80]

Proposed change

As already possible for aother registers of the climate entity, this PR add the write_registers support also in Fan Mode. The new parameter is optional and its default value is False.

Type of change

• [ ] Dependency upgrade
• [ ] Bugfix (non-breaking change which fixes an issue)
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• [ ] Deprecation (breaking change to happen in the future)
• [ ] Breaking change (fix/feature causing existing functionality to break)
• [ ] Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: https://github.com/home-assistant/home-assistant.io/pull/30838

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[crug80]

How do you validate that the configuration is not "= [1,2,3]"

I don't and I don't take in care of that because we use only the first parameter. Do you want the same approach used for target temp validation of addresses in order to raise an error in case of list greater than 1?

[janiversen]

Validation is all about filtering out faulty configurations so of course if the list have a wrong number of elements it needs to be signaled,

[crug80]

LGTM, Thanks.

Thanks you, @janiversen for your patience. I learned a lot from these experiences, in case you want/need, I'm available to collaborate.