Fix tree generators working on the unbuffered underlying world. (#2705)
Adds two methods to EditSession to allow getting blocks which are buffered by the EditSession, not yet set in the world.
This allows the proxies used by tree generators to know the eventual state of the world, rather than the "real" state. (f002c034 by wizjany)
Just re-throw here given it's already an extremely niche condition and will block commands
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Co-authored-by: Maddy Miller <mnmiller1@me.com> (b0c14624 by sirywell)
Add parent dir to manifest classpath to account for paper-remapped load point.
Currently, the remapped WorldEdit jar on paper is loaded from a sub-directory of the plugins folder, meaning dependencies like truezip and rhino won't be found in the documented search locations. Adding the parent dir temporarily solves this.
See #2692.
Closes #2691. (db49cea6 by wizjany)
