Hello longhorn17
The Swiss Travel Pass does not grant a reduction on the Lindt & Sprüngli museum admission. But, you can travel there for free with your Swiss Travel Pass.
How to benefit from a reduced entry ticket? You can purchase the RailAway leisure offer (train & entry) instead, while you only need the admission since you already hold a valid ticket:
https://www.sbb.ch/en/buying/pages/freizeit/freizeit.xhtml?produktid=820924
Select the option: Individual journey not including public transport
By doing so, you will simply benefit from a discounted museum entry ticket. For the train travel, you can use your Swiss Travel Pass.
Does that make sense?
Kind regards,
Roland