Removed the /fill command as an alias of /material.

Fixes WORLDEDIT-3016.

CHANGELOG.txt

@@ -26,6 +26,8 @@
 - Added usage of non-existent variables in all LValue expressions.
 - Changed /up and /ceil command to use glass block by default. Flight can be 
   done via -f flag now.
+- Removed the /fill command as an alias of /material (which sets the brush
+  material).
 - Fixed //deform not doing anything at all.
 - Fixed //walls on non-cuboid regions so that they no longer introduces gaps 
   in walls beyond 45 degrees.

src/main/java/com/sk89q/worldedit/commands/ToolUtilCommands.java

@@ -109,7 +109,7 @@ public class ToolUtilCommands {
     }
 
     @Command(
-        aliases = { "mat", "material", "fill" },
+        aliases = { "mat", "material" },
         usage = "[pattern]",
         desc = "Set the brush material",
         min = 1,