I've changed the item infobox in a way that it now automatically links to the item type's category, but only if no brackets are used. This is important because already before that, no brackets also were necessary to use the infobox's automatic categorization. No manual adding of those needed.
@ 2: When we're reflecting word by word what is written in the game, why a wiki then? No, just joking. Well, infoboxes shall present information exactly, unambigously, comprehensibly and briefly. Admitted, "+1" is shorter than "-1 bonus", but it's also more clear: no doubt what it does. The reader can still interprete the "bonus" as being the same what is meant in-game with the plus. It's established praxis on the BGW, and it is in the explanation of the infobox, which was not written by me. ;) I usually put something less deviating into items' descriptions on the article, like "adds a bonus of 1 to the AC" or something.