Trees should be generated on the main thread

- Also remove warning when using tree tool

worldedit-bukkit/src/main/java/com/sk89q/worldedit/bukkit/BukkitWorld.java

@@ -23,6 +23,7 @@ import com.fastasyncworldedit.bukkit.util.WorldUnloadedException;
 import com.fastasyncworldedit.core.Fawe;
 import com.fastasyncworldedit.core.queue.IChunkGet;
 import com.fastasyncworldedit.core.queue.implementation.packet.ChunkPacket;
+import com.fastasyncworldedit.core.util.TaskManager;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
 import com.sk89q.jnbt.CompoundTag;
@@ -329,7 +330,8 @@ public class BukkitWorld extends AbstractWorld {
 
     @Override
     public boolean generateTree(TreeGenerator.TreeType type, EditSession editSession, BlockVector3 pt) {
-        return WorldEditPlugin.getInstance().getBukkitImplAdapter().generateTree(type, editSession, pt, getWorld());
+        return TaskManager.IMP.sync(() -> WorldEditPlugin.getInstance().getBukkitImplAdapter().generateTree(type, editSession, pt,
+                getWorld()));
     }
 
     @Override

worldedit-core/src/main/java/com/sk89q/worldedit/command/ToolCommands.java

@@ -242,9 +242,6 @@ public class ToolCommands {
                     TreeGenerator.TreeType type
     ) throws WorldEditException {
         setTool(player, session, new TreePlanter(type), "worldedit.tool.tree.equip");
-        //FAWE start
-        player.print(TextComponent.of("Warning: This brush is currently not undo-able due to a Spigot bug!").color(TextColor.RED));
-        //FAWE end
     }
 
     @Command(