Would it be possible to, well, rename the combat-usable restorers a bit to indicate that they are combat-usable?
Uh, you mean something like put the word "insta-" at the beginning of all their names to indicate they work instantly, as opposed to over a little bit of time?
Or, maybe, have the description of the item call it fast-acting?
Or, perhaps, putting a note in the item popup calling it "combat-usable" versus "usable"?
I've already done exactly what you've asked, in three different ways. If you're that concerned about it and you *still* can't tell, frankly I don't know what else I can do to the item to make it more apparent which is which.