Add help for spawn eggs and name tags

mods/ENTITIES/mobs/crafts.lua

@@ -4,6 +4,8 @@ local S = mobs.intllib
 -- name tag
 minetest.register_craftitem("mobs:nametag", {
 	description = S("Name Tag"),
+	_doc_items_longdesc = S("A name tag is an item to name most animals and monsters."),
+	_doc_items_usagehelp = S("Rightclick an animal or monster while holding the name tag, then enter a name."),
 	inventory_image = "mobs_nametag.png",
 	wield_image = "mobs_nametag.png",
 	stack_max = 64,