rev 1: initial production version.

rev 2 (production only): disabled island generation.

rev 3: witch drops brown mushroom.

rev 4: structure books function correctly in other dimensions.
       wandering traders announce their arrival.

rev 5: trade cycling for wandering traders.

rev 6: endcity chests now give chorus flower.

rev 7: initlal 1.17 bring up.
       recipes:
       nerfed iron & gold ore crafting: recipe yields 8 -> 3.
       new recipes:
       cobbled deepslate:
         8 cobblestone + 1 gravel -> 4 cobbled deepslate
       tuff:
         8 basalt + 1 obsidian -> 9 tuff
       calcite:
         8 dripstone + 1 bonemeal -> 8 calcite

       loot tables:
         fishing loot table reverted to vanilla

       wandering traders:
       wandering traders no longer sell shulker spawn eggs.
       end city in a book price adjusted: 30 shulker shells -> 30 ender chests.
       wandering traders sells glow lichen for 5 diamonds.
       wandering traders sells geodes book for 30 emeralds.
       wandering traders sells dungeon book for 30 golden apples.
       
       structure books:
         dungeon in a book
           - always 9x6x9 and with a roof
           - only generates the spawner if used while standing on a gold block
           - always generates with two chests, one with dungeon loot,
           one with mineshaft loot (for glow berries).
         geode in a book
           - always bound within a 11x11x11 cube
           - must be used while standing on a diamond block, otherwise generates
           without budding amethyst.
           - 16~40 budding amethysts tries to generate, if the prerequisite is met.
           
       general:
         building limits adjusted to their 1.18 values.