this API is simultaneously more powerful and cleaner than the previous system.
The previous system relied on undocumented behaviour and was limited to non-localizable strings.
This enables custom servers to implement their own chat formats (e.g. containing localizable tags) which will be displayed in each player's own language (once per-player language has been properly implemented, anyway).
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
in vanilla, it appears to behave as if the player always clicked on the up face if a block was replaced.
In PM, we were still using the original face, which caused bugs when, for example, placing a button next to a wall by clicking on the side of tallgrass. The button would replace the tallgrass, but stick to the wall, instead of placing itself on the ground like vanilla expects.
This may appear unusual to anyone who also happens to implement canBePlacedAt(), since the facing behaviour will be different. However, this behaviour appears to match vanilla, and even slabs (which I feared might break because of this change) work perfectly.
In the future, it may be desirable to pass some other value here, such as null, to indicate that the clicked block is being replaced. However, that's a BC break and therefore outside of the scope of a stable bug fix.
this unintentionally allowed translations to reference other translations 1 level deep, which is not desired behaviour.
This also improves performance for the cases where formatting isn't used.
