chore: replace deprecated vim.validate({}) form

[MarkSverdlov]

Hello,
:checkhealth raises warning due to the old form of vim.validate. See https://neovim.io/doc/user/lua/#vim.validate() for details.
I changed the form to the recommended one.
Seems to work fine.

[dimtion]

Thank you for the PR!

I ran the test suite against it, it looks like older versions of nvim are expecting the older validation syntax. Could you maybe create a polyfill (a local function) that would either call the new syntax or the old syntax based on the version of nvim?

I gave you more rights to run the tests you should be able to trigger them upon PR updates.

[MarkSverdlov]

Hi, I added a polyfill function that checks the version using the vim.fn.has("nvim-0.11") api and it passes the test. I don't know lua well, and I'd like your advice if perhaps something like:

-- Validate arguments using a compatibility wrapper for vim.validate.
-- Falls back to the legacy signature on older Neovim versions.
if vim.fn.has("nvim-0.11") == 1 then
  validate = function(name, value, validator, optional, message)
    return vim.validate(name, value, validator, optional, message)
  end
else
  validate = function(name, value, validator, optional, message)
    return vim.validate({ [name] = { value, validator, optional, message } })
  end
end

Would be better as the plugin will check version only once (supposedly) instead on every call?

[dimtion]

It would be better, however, since the validate function is called only a handful of time, and is not on the plugin hot path, the difference is probably imperceptible.

If you want to do that improvement go ahead! Else I'm ok to merge that PR as is.

[MarkSverdlov]

done