I also got used to the google shopping suggestion links being blocked, the same way suggested "ad" web links are. Unfortunately due to the nature of pi-hole domain blocker, I can't think of a solution with (unless you check out mister.gnod's suggestion which is a cool hack, but by having access to firefox to add a .pem cert, you might as well use adblock and white list www.googleadservices.com in pihole)
When I was asked how come the google suggested shopping didn't work, I simply informed them their are better places to find deals. Users that are aware they can search (with practice) places like ebay, amazon or bestbuy they won't miss google suggestions a bit!