FakeInventory can cause inventory display stack counts to overlap

[ThinkInvis]

Stack text has a new system (it used to use a TextMeshPro, now uses SpriteAsNumberManager) which has absolutely no support for newlines, which were kind of necessary to make the fake item display fit. Was also forced to ditch the plus sign (e.g. "x3+5" for 3 real and 5 fake items) and use another x, which would also be nice to find a fix for.