Use reflection to locate BlockTypeIds and ItemTypeIds for VanillaBlocks/VanillaItems
Since BlockTypeIds and ItemTypeIds are derived from VanillaBlocks and VanillaItems respectively anyway (they only exist to allow identifying blocks/items without having to create instances of them), this hack is probably OK, and reduces the chances of mistakes.
Previously it was explored to have these IDs generated by auto-incrementing in VanillaBlocks/Items and have the constants generated that way, but this proved to be too problematic because of unstable diffs no matter how we chose to sort the elements. See #6313 for previous research on the subject.
This is obviously not a desirable hack to keep long-term. In the future it will probably make sense to redesign VanillaBlocks like so:
enum VanillaBlocks { ... }
VanillaBlocks::STONE (the type ID)
VanillaBlocks::STONE->new() (to create a block)
However, more research is needed on this, as I'd prefer not to make block creation any more verbose.
if an enchanted book is obtained via /give without enchantments, it should be able to receive enchantments in an enchanting table, exactly the same as regular books.
TreeType really belongs in the generator package. Not all types of tree may have their own boat type (e.g. azalea).
We can't use WoodType for this either, because some types of wood also don't have associated boat types (crimson, warped).
now that the colour and skull type are included in the block type data, it's no longer necessary to maintain shim items to retain this information in the item data.
this makes it easier to spot errors.
there's nothing we can do about the metadata values, but IDs can be quite easily constified.
there might be some weird artifacts where constants are aliased (e.g. appleenchanted) , but this is inarguably better than baking numeric IDs.
we don't usually add VanillaItems entries for blocks since they already exist in VanillaBlocks, but air has a special use case specifically as an itemstack, so we make an exception for this case.
this doesn't implement the server-side logic for the "stickiness" (slowdown) because we don't have the system needed for it yet.
It also doesn't have parity with vanilla on the damage.
