Fix a few bugs in tool commands

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

@@ -86,7 +86,7 @@ public class ToolUtilCommands {
 
     @Command(
         name = "material",
-        aliases = { "material" },
+        aliases = { "/material" },
         desc = "Set the brush material"
     )
     @CommandPermissions("worldedit.brush.options.material")

worldedit-core/src/main/java/com/sk89q/worldedit/util/TreeGenerator.java

@@ -65,8 +65,8 @@ public class TreeGenerator {
             }
         },
         JUNGLE("Jungle tree", "jungle"),
-        SMALL_JUNGLE("Small jungle tree", "shortjungle", "smalljungle"),
+        SMALL_JUNGLE("Small jungle tree", "smalljungle"),
-        SHORT_JUNGLE("Short jungle tree") {
+        SHORT_JUNGLE("Short jungle tree", "shortjungle") {
             @Override
             public boolean generate(EditSession editSession, BlockVector3 pos) throws MaxChangedBlocksException {
                 return SMALL_JUNGLE.generate(editSession, pos);