I'm trying to translate the word Tax to VAT throughout the site (specifically on the invoice PDF but I'll settle for anything at this point) and I cannot get it to change, I've overridden the tax.phtml template files and changed __("Tax") to just "VAT" but no luck and I've added a translation in for "Tax", "VAT" and it's still not updating for me.
I am on Magento 2.2
