Mishap for "no placeable block in hotbar" is both untranslated and misleading

[Robotgiggle]

Minecraft version

1.20.1

Hex Casting version

0.11.3

Issue description

If no placeable item can be found in your hotbar, Place Block will throw MishapBadOffhandItem.of(ItemStack.EMPTY, "placeable"). The lang key this generates, hexcasting.mishap.bad_item.placeable, does not exist, leading to the following mishap message:

Furthermore, even if the lang key did exist, this message would still be misleading. It claims that the spell needed something in the offhand that wasn't present, but Place Block checks through your entire hotbar, not just the offhand.

Steps to reproduce

1. Have no placeable items in your hotbar
2. Try to cast Place Block
3. Observe broken mishap message