This has several advantages:
Easier to implement new blocks (one less file to modify)
Easier to adjust serialization of existing blocks
Guaranteed consistency between serializers and deserializers
Potentially, exposes more metadata for programmatic analysis, instead of having everything baked inside opaque Closures
There are some exceptions which still use the old approach: big dripleaf, cauldrons, mushroom stems, and pitcher crops. These all have multiple PM block types for a single ID, with relatively complex logic to select which to use. These weren't worth the effort to unify due to their small number. I may revisit this in the future, but I already spent a lot of brainpower on it.
fixes#5858
technically speaking, the sideways states for non-fully-grown stems shouldn't exist, but they do in Bedrock, and changing this code to split non-fully-grown stems from fully grown ones would likely require BC breaks.
This was the minimum necessary to achieve the desired functionality.
due to technical limitations, this requires separating them back into two different block types. However, this isn't too egregious since it's just one flag, and actually simplifies some code.
closes#5478
this doesn't match the 1.16+ behaviour yet, but it at least recognizes walls that are already in the post-1.16 way and doesn't break them if not interacted with.
