Remove duplicate items from “Local Blacklist”

If I add items to “Local Blacklist” that later end up in “Disallowed Comment Keys”, such as via a pull request that eventually gets merged, I want to remove all those duplicates.

I was thinking upon each save to run de-dup, and personally I’d prefer that, but I could see some people not. So either do it that way but give an option/filter to disable automatic — and/or add a button to run it manually.

Doing only a de-dup button is probably the safest way to implement it and keep everyone happy (no surprises on removing without asking due to automatic plugin update).