Fix @param docs for $deriver on plugin attribute classes

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Rebased

Searched for @param string|null $deriver and there are 10 instances that were all replaced.

Agree on the one param change, it's own ticket would be overkill

Committed/pushed to 11.x and cherry-picked to 10.3.x, thanks!

catch → closed merge request !6945

Automatically closed - issue fixed for 2 weeks with no activity.