[2024] How am I supposed to know that I can't build IE and Navori together in game?

I recently found out about something called Item Groups in League of Legends. https://leagueoflegends.fandom.com/wiki/Item_group

Items in the same group cannot be build together because they might be too synergistic. However, in-game, there is no such indication that these items cannot actually be built together. Another example is Trailblazer and Dead man's plate, or Void Staff and Cryptbloom (though these two at least share a common component).

There _used_ to be an indication under the item name to signify what group it belongs to (eg. Mythic), which let players know they cannot be built together. I see no reason why that slot cannot now contain names of item groups.