I was going to make a PR, however I was having gradle issues as my setup required gradle 4.5 at the least and there was no one click update.

Port Localizator Mixins that add optional lang key usage for set bonus names

Mixins:
https://github.com/KameiB/Localizator/blob/master/src/main/java/kameib/localizator/mixin/setbonus/TooltipRendererMixin.java

Example Lang file with Localizator Mixins
https://github.com/fonnymunkey/RLCraft-Dregora-Edition/blob/RLCraft-Dregora/export/overrides/resources/setbonus/lang/en_us.lang
Example setbonus config using lang keys
https://github.com/fonnymunkey/RLCraft-Dregora-Edition/blob/RLCraft-Dregora/export/overrides/config/setbonus/1.12.2.009%2B.cfg#L259

Good idea, putting it on my TODO list

This is now a thing in the latest release (1.12.2.036)